move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/cmd/connclose/.gitignore

@@ -0,0 +1,2 @@
+connclose
+secret.yml

pkg/gotd/cmd/connclose/Dockerfile

@@ -0,0 +1,3 @@
+FROM ubuntu:latest
+COPY connclose /usr/sbin/connclose
+ENTRYPOINT ["/usr/sbin/connclose"]

pkg/gotd/cmd/connclose/Makefile

@@ -0,0 +1,42 @@
+all: connclose
+
+connclose:
+	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -trimpath -buildvcs=false -o connclose .
+.PHONY: connclose
+
+image: connclose
+	docker build -t connclose:latest .
+
+image-load:
+	kind load docker-image connclose:latest
+
+deploy:
+	kubectl apply -f secret.yml -f deployment.yml -f network.yml -f network.allow.yml
+
+start:
+	bash start.sh
+
+down:
+	kind delete cluster
+
+restart:
+	kubectl rollout restart deployment bot
+
+update: image image-load restart
+
+allow:
+	kubectl apply -f network.allow.yml
+
+deny:
+	kubectl apply -f network.deny.yml
+
+wait:
+	kubectl rollout status deployment bot
+
+logs:
+	kubectl logs -l app=bot
+
+follow:
+	kubectl logs -f -l app=bot
+
+up: start image image-load deploy wait

pkg/gotd/cmd/connclose/README.md

@@ -0,0 +1,56 @@
+This project is an attempt to reproduce connection timeout that causes gotd to hang.
+
+> [!WARNING]
+> Currently I'm unable to reproduce the issue.
+
+Referenced issue: https://github.com/gotd/td/issues/1030
+
+Dependencies:
+- docker
+- kind
+- helm
+- cilium cli
+- go
+
+## Preparation
+
+```bash
+cp secret.example.yml secret.yml
+```
+
+Edit `secret.yml` and put there your bot and application credentials.
+
+## Running
+
+Start cluster:
+
+```bash
+make up
+```
+
+Deny connections to telegram:
+```bash
+make deny
+```
+
+Update binary
+```bash
+make update
+```
+
+Restore connections
+```bash
+make allow
+```
+
+## Logs
+
+```bash
+make logs
+```
+
+## Cleanup
+
+```bash
+make down
+```

pkg/gotd/cmd/connclose/deployment.yml

@@ -0,0 +1,65 @@
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: bot
+  labels:
+    app.kubernetes.io/name: bot
+spec:
+  strategy:
+    type: Recreate
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: bot
+  template:
+    metadata:
+      labels:
+        app: bot
+        app.kubernetes.io/name: bot
+    spec:
+      containers:
+        - name: bot
+          image: connclose:latest
+          imagePullPolicy: Never
+          resources:
+            requests:
+              cpu: 500m
+              memory: 128M
+            limits:
+              cpu: 1000m
+              memory: 256M
+          env:
+            - name: GOMEMLIMIT
+              value: "128MiB"
+            - name: GOMAXPROCS
+              value: "2"
+            - name: OTEL_METRICS_EXPORTER
+              value: "prometheus"
+            - name: OTEL_EXPORTER_PROMETHEUS_PORT
+              value: "8090"
+            - name: OTEL_EXPORTER_PROMETHEUS_HOST
+              value: "0.0.0.0"
+            - name: PPROF_ADDR
+              value: "0.0.0.0:8090"
+            - name: OTEL_RESOURCE_ATTRIBUTES
+              value: "service.name=connclose"
+            - name: OTEL_LOG_LEVEL
+              value: "DEBUG"
+            - name: OTEL_TRACES_EXPORTER
+              value: "none"
+            - name: BOT_TOKEN
+              valueFrom:
+                secretKeyRef:
+                  name: config
+                  key: BOT_TOKEN
+            - name: APP_ID
+              valueFrom:
+                secretKeyRef:
+                  name: config
+                  key: APP_ID
+            - name: APP_HASH
+              valueFrom:
+                secretKeyRef:
+                  name: config
+                  key: APP_HASH

pkg/gotd/cmd/connclose/kind.yml

@@ -0,0 +1,7 @@
+kind: Cluster
+apiVersion: kind.x-k8s.io/v1alpha4
+nodes:
+  - role: control-plane
+  - role: worker
+networking:
+  disableDefaultCNI: true

pkg/gotd/cmd/connclose/main.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/signal"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram/message"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+func run(ctx context.Context) error {
+	logger, _ := zap.NewDevelopment(zap.IncreaseLevel(zapcore.DebugLevel))
+	defer func() { _ = logger.Sync() }()
+
+	dispatcher := tg.NewUpdateDispatcher()
+	return telegram.BotFromEnvironment(ctx, telegram.Options{
+		Logger:        logger,
+		UpdateHandler: dispatcher,
+	}, func(ctx context.Context, client *telegram.Client) error {
+		sender := message.NewSender(tg.NewClient(client))
+		dispatcher.OnNewMessage(func(ctx context.Context, entities tg.Entities, u *tg.UpdateNewMessage) error {
+			m, ok := u.Message.(*tg.Message)
+			if !ok || m.Out {
+				return nil
+			}
+
+			_, err := sender.Reply(entities, u).Text(ctx, m.Message)
+			return err
+		})
+		return nil
+	}, telegram.RunUntilCanceled)
+}
+
+func main() {
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer cancel()
+
+	if err := run(ctx); err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "%+v\n", err)
+		os.Exit(2)
+	}
+}

pkg/gotd/cmd/connclose/network.allow.yml

@@ -0,0 +1,31 @@
+apiVersion: cilium.io/v2
+kind: CiliumNetworkPolicy
+metadata:
+  name: telegram
+spec:
+  endpointSelector:
+    matchLabels:
+      app.kubernetes.io/name: bot
+  egress:
+    - # telegram datacenters list
+      # generated by cmd/dcsidr
+      toCIDRSet:
+        - cidr: 149.154.175.59/32
+        - cidr: 149.154.175.53/32
+        - cidr: 2001:b28:f23d:f001::a/128
+        - cidr: 149.154.167.50/32
+        - cidr: 149.154.167.51/32
+        - cidr: 149.154.167.151/32
+        - cidr: 2001:67c:4e8:f002::a/128
+        - cidr: 2001:67c:4e8:f002::b/128
+        - cidr: 149.154.175.100/32
+        - cidr: 2001:b28:f23d:f003::a/128
+        - cidr: 149.154.167.91/32
+        - cidr: 2001:67c:4e8:f004::a/128
+        - cidr: 149.154.166.120/32
+        - cidr: 2001:67c:4e8:f004::b/128
+        - cidr: 2001:b28:f23f:f005::a/128
+        - cidr: 91.108.56.173/32
+      toPorts:
+        - ports:
+            - port: "443"

pkg/gotd/cmd/connclose/network.deny.yml

@@ -0,0 +1,10 @@
+apiVersion: cilium.io/v2
+kind: CiliumNetworkPolicy
+metadata:
+  name: telegram
+spec:
+  endpointSelector:
+    matchLabels:
+      app.kubernetes.io/name: bot
+  # None.
+  egress: []

pkg/gotd/cmd/connclose/network.yml

@@ -0,0 +1,20 @@
+apiVersion: cilium.io/v2
+kind: CiliumNetworkPolicy
+metadata:
+  name: dns
+spec:
+  endpointSelector:
+    matchLabels:
+      app.kubernetes.io/name: bot
+  egress:
+    - toEndpoints:
+        - matchLabels:
+            io.kubernetes.pod.namespace: kube-system
+            k8s-app: kube-dns
+      toPorts:
+        - ports:
+            - port: "53"
+              protocol: UDP
+          rules:
+            dns:
+              - matchPattern: "*"

pkg/gotd/cmd/connclose/secret.example.yml

@@ -0,0 +1,10 @@
+---
+apiVersion: v1
+kind: Secret
+type: Opaque
+metadata:
+  name: config
+stringData:
+  BOT_TOKEN: "1111111111:AAG1SomeBotTokenFromBotFather-1337a"
+  APP_ID: "0123456"
+  APP_HASH: "0123456789abcdef0123456789abcdef"

pkg/gotd/cmd/connclose/start.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+set -ex
+
+kind create cluster --config kind.yml
+docker pull quay.io/cilium/cilium:v1.14.6
+kind load docker-image quay.io/cilium/cilium:v1.14.6
+
+helm install cilium cilium/cilium --version 1.14.6 \
+   --namespace kube-system \
+   --set image.pullPolicy=IfNotPresent \
+   --set ipam.mode=kubernetes
+
+cilium status --wait

pkg/gotd/cmd/dlkey/main.go

@@ -0,0 +1,59 @@
+// Binary dlkey extracts public keys from remote repo.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"path"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/keyparser"
+)
+
+func main() {
+	var (
+		name   = flag.String("f", "mtproto_dc_options.cpp", "file name to download")
+		base   = flag.String("base", "https://raw.githubusercontent.com/telegramdesktop/tdesktop", "base url")
+		branch = flag.String("branch", "dev", "branch to use")
+		dir    = flag.String("dir", "Telegram/SourceFiles/mtproto/", "directory")
+		out    = flag.String("o", "", "output file name (blank to stdout)")
+	)
+	flag.Parse()
+
+	u, err := url.Parse(*base)
+	if err != nil {
+		panic(err)
+	}
+
+	u.Path = path.Join(u.Path, *branch, *dir, *name)
+
+	res, err := http.Get(u.String())
+	if err != nil {
+		panic(err)
+	}
+	defer func() { _ = res.Body.Close() }()
+	if res.StatusCode/100 != 2 {
+		panic(fmt.Sprintf("status code %d", res.StatusCode))
+	}
+
+	var outWriter io.Writer = os.Stdout
+	if *out != "" {
+		w, err := os.Create(*out)
+		if err != nil {
+			panic(err)
+		}
+		defer func() {
+			if err := w.Close(); err != nil {
+				panic(err)
+			}
+		}()
+		outWriter = w
+	}
+
+	if err := keyparser.Extract(res.Body, outWriter); err != nil {
+		panic(err)
+	}
+}

pkg/gotd/cmd/dltl/main.go

@@ -0,0 +1,168 @@
+// Binary dltl fetches .tl schema from remote repo.
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/sha256"
+	"flag"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+
+	"github.com/gotd/tl"
+)
+
+func mergeSchema(target, s *tl.Schema) {
+Definitions:
+	for _, d := range s.Definitions {
+		for _, targetD := range target.Definitions {
+			if targetD.Definition.ID == d.Definition.ID {
+				continue Definitions
+			}
+		}
+
+		target.Definitions = append(target.Definitions, d)
+	}
+Classes:
+	for _, c := range s.Classes {
+		for _, targetC := range target.Classes {
+			if targetC.Name == c.Name {
+				continue Classes
+			}
+		}
+
+		target.Classes = append(target.Classes, c)
+	}
+	if target.Layer == 0 {
+		target.Layer = s.Layer
+	}
+}
+
+func main() {
+	var (
+		name   = flag.String("f", "telegram_api.tl", "file name to download; api.tl or mtproto.tl")
+		base   = flag.String("base", "https://raw.githubusercontent.com/tdlib/td", "base url")
+		branch = flag.String("branch", "master", "branch to use")
+		dir    = flag.String("dir", "td/generate/scheme", "directory of schemas")
+		out    = flag.String("o", "", "output file name (blank to stdout)")
+		merge  = flag.String("merge", "", "path to schema(s) to merge with, comma-separated")
+	)
+	flag.Parse()
+
+	u, err := url.Parse(*base)
+	if err != nil {
+		panic(err)
+	}
+
+	u.Path = path.Join(u.Path, *branch, *dir, *name)
+
+	res, err := http.Get(u.String())
+	if err != nil {
+		panic(err)
+	}
+	defer func() { _ = res.Body.Close() }()
+	if res.StatusCode/100 != 2 {
+		panic(fmt.Sprintf("%s %d", u.String(), res.StatusCode))
+	}
+
+	// Parsing in-place.
+	h := sha256.New()
+	s, err := tl.Parse(io.TeeReader(res.Body, h))
+	if err != nil {
+		panic(err)
+	}
+
+	if *merge != "" {
+		for _, mergeName := range strings.Split(*merge, ",") {
+			data, err := os.ReadFile(mergeName)
+			if err != nil {
+				panic(err)
+			}
+
+			m, err := tl.Parse(bytes.NewReader(data))
+			if err != nil {
+				panic(err)
+			}
+
+			mergeSchema(s, m)
+		}
+	}
+
+	// Trying to detect layer of tdlib schema.
+	if s.Layer == 0 && *name == "telegram_api.tl" {
+		layerURL, err := url.Parse(*base)
+		if err != nil {
+			panic(err)
+		}
+		layerURL.Path = path.Join(layerURL.Path, *branch, "td/telegram/Version.h")
+		res, err := http.Get(layerURL.String())
+		if err != nil {
+			panic(err)
+		}
+		if res.StatusCode == http.StatusOK {
+			scanner := bufio.NewScanner(res.Body)
+			for scanner.Scan() {
+				t := strings.TrimSpace(scanner.Text())
+				// constexpr int32 MTPROTO_LAYER = 131;
+				const (
+					prefix = `constexpr int32 MTPROTO_LAYER = `
+					suffix = `;`
+				)
+				if !strings.HasPrefix(t, prefix) {
+					continue
+				}
+				t = strings.TrimPrefix(t, prefix)
+				t = strings.TrimSuffix(t, suffix)
+				t = strings.TrimSpace(t)
+				if layer, err := strconv.Atoi(t); err == nil {
+					s.Layer = layer
+				}
+			}
+		}
+	}
+	if s.Layer == 0 && *name == "telegram_api.tl" {
+		// Still failed.
+		panic("failed to detect layer")
+	}
+
+	var outWriter io.Writer = os.Stdout
+	if *out != "" {
+		w, err := os.Create(*out)
+		if err != nil {
+			panic(err)
+		}
+		defer func() {
+			if err := w.Close(); err != nil {
+				panic(err)
+			}
+		}()
+		outWriter = w
+	}
+
+	// Writing header to avoid manual edit.
+	var b strings.Builder
+	b.WriteString("// Code generated by ./cmd/dltl, DO NOT EDIT.\n")
+	b.WriteString("//\n")
+	b.WriteString(fmt.Sprintf("// Source: %s\n", u))
+	if *merge != "" {
+		b.WriteString(fmt.Sprintf("// Merge:  %s\n", *merge))
+	}
+	if s.Layer > 0 {
+		b.WriteString(fmt.Sprintf("// Layer:  %d\n", s.Layer))
+	}
+	b.WriteString(fmt.Sprintf("// SHA256: %x\n", h.Sum(nil)))
+	b.WriteRune('\n')
+	if _, err := io.WriteString(outWriter, b.String()); err != nil {
+		panic(err)
+	}
+
+	if _, err := s.WriteTo(outWriter); err != nil {
+		panic(err)
+	}
+}

pkg/gotd/cmd/dscidr/main.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+	"fmt"
+	"net/netip"
+	"os"
+
+	"gopkg.in/yaml.v3"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram/dcs"
+)
+
+type CIDRElement struct {
+	CIDR string `json:"cidr" yaml:"cidr"`
+}
+
+type Ports struct {
+	Ports []Port `json:"ports" yaml:"ports"`
+}
+
+type Port struct {
+	Port string `json:"port" yaml:"port"`
+}
+
+type Element struct {
+	ToCIDRSet []CIDRElement `json:"toCIDRSet" yaml:"toCIDRSet"`
+	ToPorts   []Ports       `json:"toPorts" yaml:"toPorts"`
+}
+
+/*
+
+- toCIDRSet:
+   - cidr: 192.169.0.1/32
+  toPorts:
+   - ports:
+	   - port: "443"
+*/
+
+func main() {
+	list := dcs.Prod()
+	var out []CIDRElement
+	met := make(map[string]struct{})
+	for _, v := range list.Options {
+		ip, err := netip.ParseAddr(v.IPAddress)
+		if err != nil {
+			panic(err)
+		}
+		if v.Port != 443 {
+			panic("port != 443")
+		}
+		prefix := netip.PrefixFrom(ip, ip.BitLen())
+		cidr := prefix.String()
+		if _, ok := met[cidr]; ok {
+			continue
+		}
+		met[cidr] = struct{}{}
+		out = append(out, CIDRElement{CIDR: cidr})
+	}
+	fmt.Println("# telegram datacenters list")
+	fmt.Println("# generated by cmd/dcsidr")
+	e := yaml.NewEncoder(os.Stdout)
+	e.SetIndent(2)
+	if err := e.Encode(Element{
+		ToCIDRSet: out,
+		ToPorts: []Ports{
+			{
+				Ports: []Port{
+					{Port: "443"},
+				},
+			},
+		},
+	}); err != nil {
+		panic(err)
+	}
+}

pkg/gotd/cmd/gotdecho/main.go

@@ -0,0 +1,49 @@
+// Binary gotdecho provides example of Telegram echo bot.
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/signal"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram/message"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+func run(ctx context.Context) error {
+	logger, _ := zap.NewDevelopment(zap.IncreaseLevel(zapcore.DebugLevel))
+	defer func() { _ = logger.Sync() }()
+
+	dispatcher := tg.NewUpdateDispatcher()
+	return telegram.BotFromEnvironment(ctx, telegram.Options{
+		Logger:        logger,
+		UpdateHandler: dispatcher,
+	}, func(ctx context.Context, client *telegram.Client) error {
+		sender := message.NewSender(tg.NewClient(client))
+		dispatcher.OnNewMessage(func(ctx context.Context, entities tg.Entities, u *tg.UpdateNewMessage) error {
+			m, ok := u.Message.(*tg.Message)
+			if !ok || m.Out {
+				return nil
+			}
+
+			_, err := sender.Reply(entities, u).Text(ctx, m.Message)
+			return err
+		})
+		return nil
+	}, telegram.RunUntilCanceled)
+}
+
+func main() {
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer cancel()
+
+	if err := run(ctx); err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "%+v\n", err)
+		os.Exit(2)
+	}
+}

pkg/gotd/cmd/gotdgen/main.go

@@ -0,0 +1,108 @@
+// Binary gotdgen generates go source code from TL schema.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"go/format"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/gotd/tl"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/gen"
+)
+
+type formattedSource struct {
+	Format bool
+	Root   string
+}
+
+func (t formattedSource) WriteFile(name string, content []byte) error {
+	out := content
+	if t.Format {
+		buf, err := format.Source(content)
+		if err != nil {
+			return err
+		}
+		out = buf
+	}
+	return os.WriteFile(filepath.Join(t.Root, name), out, 0600)
+}
+
+func main() {
+	schemaPath := flag.String("schema", "", "Path to .tl file")
+	targetDir := flag.String("target", "td", "Path to target dir")
+	packageName := flag.String("package", "td", "Target package name")
+	performFormat := flag.Bool("format", true, "Perform code formatting")
+	clean := flag.Bool("clean", false, "Clean generated files before generation")
+
+	genOpts := gen.GeneratorOptions{}
+	genOpts.RegisterFlags(flag.CommandLine)
+
+	flag.Parse()
+	if *schemaPath == "" {
+		panic("no schema provided")
+	}
+	f, err := os.Open(*schemaPath)
+	if err != nil {
+		panic(err)
+	}
+	defer func() { _ = f.Close() }()
+
+	schema, err := tl.Parse(f)
+	if err != nil {
+		panic(err)
+	}
+	files, err := os.ReadDir(*targetDir)
+	if err != nil && !os.IsNotExist(err) {
+		panic(err)
+	}
+	if os.IsNotExist(err) {
+		if err := os.Mkdir(*targetDir, 0750); err != nil {
+			panic(err)
+		}
+	}
+	if *clean {
+		for _, f := range files {
+			if f.IsDir() {
+				continue
+			}
+			name := f.Name()
+			if !strings.HasSuffix(name, "_gen.go") {
+				continue
+			}
+			if !strings.HasPrefix(name, "tl_") {
+				continue
+			}
+			if err := os.Remove(filepath.Join(*targetDir, name)); err != nil {
+				panic(err)
+			}
+		}
+	}
+
+	start := time.Now()
+	fs := formattedSource{
+		Root:   *targetDir,
+		Format: *performFormat,
+	}
+	g, err := gen.NewGenerator(schema, genOpts)
+	if err != nil {
+		panic(fmt.Sprintf("%+v", err))
+	}
+	collectInfoTime := time.Since(start)
+
+	start = time.Now()
+	if err := g.WriteSource(fs, *packageName, gen.Template()); err != nil {
+		panic(fmt.Sprintf("%+v", err))
+	}
+	writeTime := time.Since(start)
+
+	fmt.Printf("Generation %s complete, collect time: %s, write time: %s\n",
+		*packageName,
+		collectInfoTime,
+		writeTime,
+	)
+}

pkg/gotd/cmd/mtprint/main.go

@@ -0,0 +1,31 @@
+// Binary mtprint pretty-prints MTProto message from binary file.
+package main
+
+import (
+	"flag"
+	"io"
+	"os"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/proto/codec"
+)
+
+func main() {
+	inputName := flag.String("f", "", "input file (blank for stdin)")
+	format := flag.String("format", "go", "print format")
+	flag.Parse()
+
+	var reader io.Reader = os.Stdin
+	if *inputName != "" {
+		f, err := os.Open(*inputName)
+		if err != nil {
+			panic(err)
+		}
+		defer func() { _ = f.Close() }()
+		reader = f
+	}
+
+	p := NewPrinter(reader, formats(*format), codec.Intermediate{})
+	if err := p.Print(os.Stdout); err != nil {
+		panic(err)
+	}
+}

pkg/gotd/cmd/mtprint/printer.go

@@ -0,0 +1,130 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+
+	"github.com/go-faster/errors"
+	"github.com/k0kubun/pp/v3"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/mt"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/proto/codec"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tdp"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tmap"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/transport"
+)
+
+// Object is abstraction for TL schema object.
+type Object interface {
+	bin.Object
+	tdp.Object
+}
+
+// Formatter formats given bin.Object and prints it to io.Writer.
+type Formatter interface {
+	Format(w io.Writer, i Object) error
+}
+
+// FormatterFunc is functional adapter for Formatter.
+type FormatterFunc func(w io.Writer, i Object) error
+
+// Format implements Formatter.
+func (f FormatterFunc) Format(w io.Writer, i Object) error {
+	return f(w, i)
+}
+
+func formats(name string) Formatter {
+	switch name {
+	case "json":
+		return FormatterFunc(func(w io.Writer, i Object) error {
+			e := json.NewEncoder(w)
+			e.SetIndent("", "\t")
+			return e.Encode(i)
+		})
+	case "pp":
+		return FormatterFunc(func(w io.Writer, i Object) error {
+			_, err := pp.Fprintln(w, i)
+			return err
+		})
+	case "tdp":
+		return FormatterFunc(func(w io.Writer, i Object) error {
+			_, err := io.WriteString(w, tdp.Format(i))
+			return err
+		})
+	default: // "go" format
+		return FormatterFunc(func(w io.Writer, i Object) error {
+			_, err := fmt.Fprintln(w, i)
+			return err
+		})
+	}
+}
+
+// Printer decodes messages from given reader and prints is using Formatter.
+type Printer struct {
+	src    io.Reader
+	codec  transport.Codec
+	format Formatter
+}
+
+// NewPrinter creates new Printer.
+// If format is nil, "go" format will be used.
+// If c is nil, codec.Intermediate will be use.
+func NewPrinter(src io.Reader, format Formatter, c transport.Codec) Printer {
+	if c == nil {
+		c = codec.Intermediate{}
+	}
+	if format == nil {
+		format = formats("go")
+	}
+	return Printer{
+		src:    src,
+		codec:  c,
+		format: format,
+	}
+}
+
+// Print prints decoded messages to output.
+func (p Printer) Print(output io.Writer) error {
+	b := &bin.Buffer{}
+
+	m := tmap.NewConstructor(
+		tg.TypesConstructorMap(),
+		mt.TypesConstructorMap(),
+	)
+	for {
+		b.Reset()
+		if err := p.codec.Read(p.src, b); err != nil {
+			if errors.Is(err, io.EOF) {
+				return nil
+			}
+
+			return err
+		}
+
+		id, err := b.PeekID()
+		if err != nil {
+			return err
+		}
+
+		obj := m.New(id)
+		if obj == nil {
+			return errors.Errorf("find type %#x", id)
+		}
+
+		v, ok := obj.(Object)
+		if !ok {
+			return errors.Errorf("unexpected type %T", obj)
+		}
+
+		if err := v.Decode(b); err != nil {
+			return err
+		}
+
+		if err := p.format.Format(output, v); err != nil {
+			return err
+		}
+	}
+}

pkg/gotd/cmd/mtprint/printer_test.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/mt"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/proto/codec"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+func Test_readAndPrint(t *testing.T) {
+	c := codec.Intermediate{}
+
+	input := &bytes.Buffer{}
+	buf := &bin.Buffer{}
+
+	objects := []bin.Object{
+		&mt.RPCResult{},
+		&mt.RPCError{},
+		&tg.CodeSettings{},
+	}
+	for _, o := range objects {
+		buf.Reset()
+		require.NoError(t, o.Encode(buf))
+		require.NoError(t, c.Write(input, buf))
+	}
+
+	output := &bytes.Buffer{}
+	require.NoError(t, NewPrinter(input, formats("go"), c).Print(output))
+	out := output.String()
+	require.Contains(t, out, "RPCResult")
+	require.Contains(t, out, "RPCError")
+	require.Contains(t, out, "CodeSettings")
+}

pkg/gotd/cmd/rsagen/_example/generate.go

@@ -0,0 +1,10 @@
+package example
+
+//go:generate go run go.mau.fi/mautrix-telegram/pkg/gotd/cmd/rsagen -f single.pem -single -pkg example -var SinglePK -o rsagen_single.go
+//go:generate go run go.mau.fi/mautrix-telegram/pkg/gotd/cmd/rsagen -f single.pem -single -pkg example -var SinglePK -o rsagen_single_test.go -exec test.tmpl
+
+//go:generate go run go.mau.fi/mautrix-telegram/pkg/gotd/cmd/rsagen -f many.pem -pkg example -var ManyPK -o rsagen_many.go
+//go:generate go run go.mau.fi/mautrix-telegram/pkg/gotd/cmd/rsagen -f many.pem -pkg example -var ManyPK -o rsagen_many_test.go -exec test.tmpl
+
+//go:generate go run go.mau.fi/mautrix-telegram/pkg/gotd/cmd/rsagen -pkg example -var EmptyPK -o rsagen_empty.go
+//go:generate go run go.mau.fi/mautrix-telegram/pkg/gotd/cmd/rsagen -pkg example -var EmptyPK -o rsagen_empty_test.go -exec test.tmpl

pkg/gotd/cmd/rsagen/_example/many.pem

@@ -0,0 +1,44 @@
+-----BEGIN RSA PUBLIC KEY-----
+MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6
+lyDONS789sVoD/xCS9Y0hkkC3gtL1tSfTlgCMOOul9lcixlEKzwKENj1Yz/s7daS
+an9tqw3bfUV/nqgbhGX81v/+7RFAEd+RwFnK7a+XYl9sluzHRyVVaTTveB2GazTw
+Efzk2DWgkBluml8OREmvfraX3bkHZJTKX4EQSjBbbdJ2ZXIsRrYOXfaA+xayEGB+
+8hdlLmAjbCVfaigxX0CDqWeR1yFL9kwd9P0NsZRPsmoqVwMbMu7mStFai6aIhc3n
+Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
+-----END RSA PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAruw2yP/BCcsJliRoW5eB
+VBVle9dtjJw+OYED160Wybum9SXtBBLXriwt4rROd9csv0t0OHCaTmRqBcQ0J8fx
+hN6/cpR1GWgOZRUAiQxoMnlt0R93LCX/j1dnVa/gVbCjdSxpbrfY2g2L4frzjJvd
+l84Kd9ORYjDEAyFnEA7dD556OptgLQQ2e2iVNq8NZLYTzLp5YpOdO1doK+ttrltg
+gTCy5SrKeLoCPPbOgGsdxJxyz5KKcZnSLj16yE5HvJQn0CNpRdENvRUXe6tBP78O
+39oJ8BTHp9oIjd6XWXAsp2CvK45Ol8wFXGF710w9lwCGNbmNxNYhtIkdqfsEcwR5
+JwIDAQAB
+-----END PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvfLHfYH2r9R70w8prHbl
+Wt/nDkh+XkgpflqQVcnAfSuTtO05lNPspQmL8Y2XjVT4t8cT6xAkdgfmmvnvRPOO
+KPi0OfJXoRVylFzAQG/j83u5K3kRLbae7fLccVhKZhY46lvsueI1hQdLgNV9n1cQ
+3TDS2pQOCtovG4eDl9wacrXOJTG2990VjgnIKNA0UMoP+KF03qzryqIt3oTvZq03
+DyWdGK+AZjgBLaDKSnC6qD2cFY81UryRWOab8zKkWAnhw2kFpcqhI0jdV5QaSCEx
+vnsjVaX0Y1N0870931/5Jb9ICe4nweZ9kSDF/gip3kWLG0o8XQpChDfyvsqB9OLV
+/wIDAQAB
+-----END PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAs/ditzm+mPND6xkhzwFI
+z6J/968CtkcSE/7Z2qAJiXbmZ3UDJPGrzqTDHkO30R8VeRM/Kz2f4nR05GIFiITl
+4bEjvpy7xqRDspJcCFIOcyXm8abVDhF+th6knSU0yLtNKuQVP6voMrnt9MV1X92L
+GZQLgdHZbPQz0Z5qIpaKhdyA8DEvWWvSUwwc+yi1/gGaybwlzZwqXYoPOhwMebzK
+Uk0xW14htcJrRrq+PXXQbRzTMynseCoPIoke0dtCodbA3qQxQovE16q9zz4Otv2k
+4j63cz53J+mhkVWAeWxVGI0lltJmWtEYK6er8VqqWot3nqmWMXogrgRLggv/Nbbo
+oQIDAQAB
+-----END PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvmpxVY7ld/8DAjz6F6q0
+5shjg8/4p6047bn6/m8yPy1RBsvIyvuDuGnP/RzPEhzXQ9UJ5Ynmh2XJZgHoE9xb
+nfxL5BXHplJhMtADXKM9bWB11PU1Eioc3+AXBB8QiNFBn2XI5UkO5hPhbb9mJpjA
+9Uhw8EdfqJP8QetVsI/xrCEbwEXe0xvifRLJbY08/Gp66KpQvy7g8w7VB8wlgePe
+xW3pT13Ap6vuC+mQuJPyiHvSxjEKHgqePji9NP3tJUFQjcECqcm0yV7/2d0t/pbC
+m+ZH1sadZspQCEPPrtbkQBlvHb4OLiIWPGHKSMeRFvp3IWcmdJqXahxLCUS1Eh6M
+AQIDAQAB
+-----END PUBLIC KEY-----

pkg/gotd/cmd/rsagen/_example/rsagen_empty.go

@@ -0,0 +1,14 @@
+// Code generated by rsagen, DO NOT EDIT.
+//
+//
+
+package example
+
+import (
+	"crypto/rsa"
+	"math/big"
+)
+
+var _ = (*big.Int)(nil)
+
+var EmptyPK = []*rsa.PublicKey{}

pkg/gotd/cmd/rsagen/_example/rsagen_empty_test.go

@@ -0,0 +1,24 @@
+// Code generated by rsagen, DO NOT EDIT.
+
+package example
+
+import (
+	"crypto/rsa"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/crypto"
+)
+
+func TestFingerprintEmptyPK(t *testing.T) {
+	fingerprint := func(pubkey *rsa.PublicKey) string {
+		return fmt.Sprintf("%08x", uint64(crypto.RSAFingerprint(pubkey)))
+	}
+	expected := []string{}
+	assert.Len(t, EmptyPK, len(expected))
+	for i, pubkey := range EmptyPK {
+		assert.Equal(t, expected[i], fingerprint(pubkey))
+	}
+}

pkg/gotd/cmd/rsagen/_example/rsagen_many.go

@@ -0,0 +1,244 @@
+// Code generated by rsagen, DO NOT EDIT.
+//
+// -----BEGIN RSA PUBLIC KEY-----
+// MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6
+// lyDONS789sVoD/xCS9Y0hkkC3gtL1tSfTlgCMOOul9lcixlEKzwKENj1Yz/s7daS
+// an9tqw3bfUV/nqgbhGX81v/+7RFAEd+RwFnK7a+XYl9sluzHRyVVaTTveB2GazTw
+// Efzk2DWgkBluml8OREmvfraX3bkHZJTKX4EQSjBbbdJ2ZXIsRrYOXfaA+xayEGB+
+// 8hdlLmAjbCVfaigxX0CDqWeR1yFL9kwd9P0NsZRPsmoqVwMbMu7mStFai6aIhc3n
+// Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
+// -----END RSA PUBLIC KEY-----
+// -----BEGIN PUBLIC KEY-----
+// MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAruw2yP/BCcsJliRoW5eB
+// VBVle9dtjJw+OYED160Wybum9SXtBBLXriwt4rROd9csv0t0OHCaTmRqBcQ0J8fx
+// hN6/cpR1GWgOZRUAiQxoMnlt0R93LCX/j1dnVa/gVbCjdSxpbrfY2g2L4frzjJvd
+// l84Kd9ORYjDEAyFnEA7dD556OptgLQQ2e2iVNq8NZLYTzLp5YpOdO1doK+ttrltg
+// gTCy5SrKeLoCPPbOgGsdxJxyz5KKcZnSLj16yE5HvJQn0CNpRdENvRUXe6tBP78O
+// 39oJ8BTHp9oIjd6XWXAsp2CvK45Ol8wFXGF710w9lwCGNbmNxNYhtIkdqfsEcwR5
+// JwIDAQAB
+// -----END PUBLIC KEY-----
+// -----BEGIN PUBLIC KEY-----
+// MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvfLHfYH2r9R70w8prHbl
+// Wt/nDkh+XkgpflqQVcnAfSuTtO05lNPspQmL8Y2XjVT4t8cT6xAkdgfmmvnvRPOO
+// KPi0OfJXoRVylFzAQG/j83u5K3kRLbae7fLccVhKZhY46lvsueI1hQdLgNV9n1cQ
+// 3TDS2pQOCtovG4eDl9wacrXOJTG2990VjgnIKNA0UMoP+KF03qzryqIt3oTvZq03
+// DyWdGK+AZjgBLaDKSnC6qD2cFY81UryRWOab8zKkWAnhw2kFpcqhI0jdV5QaSCEx
+// vnsjVaX0Y1N0870931/5Jb9ICe4nweZ9kSDF/gip3kWLG0o8XQpChDfyvsqB9OLV
+// /wIDAQAB
+// -----END PUBLIC KEY-----
+// -----BEGIN PUBLIC KEY-----
+// MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAs/ditzm+mPND6xkhzwFI
+// z6J/968CtkcSE/7Z2qAJiXbmZ3UDJPGrzqTDHkO30R8VeRM/Kz2f4nR05GIFiITl
+// 4bEjvpy7xqRDspJcCFIOcyXm8abVDhF+th6knSU0yLtNKuQVP6voMrnt9MV1X92L
+// GZQLgdHZbPQz0Z5qIpaKhdyA8DEvWWvSUwwc+yi1/gGaybwlzZwqXYoPOhwMebzK
+// Uk0xW14htcJrRrq+PXXQbRzTMynseCoPIoke0dtCodbA3qQxQovE16q9zz4Otv2k
+// 4j63cz53J+mhkVWAeWxVGI0lltJmWtEYK6er8VqqWot3nqmWMXogrgRLggv/Nbbo
+// oQIDAQAB
+// -----END PUBLIC KEY-----
+// -----BEGIN PUBLIC KEY-----
+// MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvmpxVY7ld/8DAjz6F6q0
+// 5shjg8/4p6047bn6/m8yPy1RBsvIyvuDuGnP/RzPEhzXQ9UJ5Ynmh2XJZgHoE9xb
+// nfxL5BXHplJhMtADXKM9bWB11PU1Eioc3+AXBB8QiNFBn2XI5UkO5hPhbb9mJpjA
+// 9Uhw8EdfqJP8QetVsI/xrCEbwEXe0xvifRLJbY08/Gp66KpQvy7g8w7VB8wlgePe
+// xW3pT13Ap6vuC+mQuJPyiHvSxjEKHgqePji9NP3tJUFQjcECqcm0yV7/2d0t/pbC
+// m+ZH1sadZspQCEPPrtbkQBlvHb4OLiIWPGHKSMeRFvp3IWcmdJqXahxLCUS1Eh6M
+// AQIDAQAB
+// -----END PUBLIC KEY-----
+//
+
+package example
+
+import (
+	"crypto/rsa"
+	"math/big"
+)
+
+var _ = (*big.Int)(nil)
+
+var ManyPK = []*rsa.PublicKey{
+	{
+		E: 65537,
+		N: new(big.Int).SetBytes([]byte{
+			0xc1, 0x50, 0x02, 0x3e, 0x2f, 0x70, 0xdb, 0x79,
+			0x85, 0xde, 0xd0, 0x64, 0x75, 0x9c, 0xfe, 0xcf,
+			0x0a, 0xf3, 0x28, 0xe6, 0x9a, 0x41, 0xda, 0xf4,
+			0xd6, 0xf0, 0x1b, 0x53, 0x81, 0x35, 0xa6, 0xf9,
+			0x1f, 0x8f, 0x8b, 0x2a, 0x0e, 0xc9, 0xba, 0x97,
+			0x20, 0xce, 0x35, 0x2e, 0xfc, 0xf6, 0xc5, 0x68,
+			0x0f, 0xfc, 0x42, 0x4b, 0xd6, 0x34, 0x86, 0x49,
+			0x02, 0xde, 0x0b, 0x4b, 0xd6, 0xd4, 0x9f, 0x4e,
+			0x58, 0x02, 0x30, 0xe3, 0xae, 0x97, 0xd9, 0x5c,
+			0x8b, 0x19, 0x44, 0x2b, 0x3c, 0x0a, 0x10, 0xd8,
+			0xf5, 0x63, 0x3f, 0xec, 0xed, 0xd6, 0x92, 0x6a,
+			0x7f, 0x6d, 0xab, 0x0d, 0xdb, 0x7d, 0x45, 0x7f,
+			0x9e, 0xa8, 0x1b, 0x84, 0x65, 0xfc, 0xd6, 0xff,
+			0xfe, 0xed, 0x11, 0x40, 0x11, 0xdf, 0x91, 0xc0,
+			0x59, 0xca, 0xed, 0xaf, 0x97, 0x62, 0x5f, 0x6c,
+			0x96, 0xec, 0xc7, 0x47, 0x25, 0x55, 0x69, 0x34,
+			0xef, 0x78, 0x1d, 0x86, 0x6b, 0x34, 0xf0, 0x11,
+			0xfc, 0xe4, 0xd8, 0x35, 0xa0, 0x90, 0x19, 0x6e,
+			0x9a, 0x5f, 0x0e, 0x44, 0x49, 0xaf, 0x7e, 0xb6,
+			0x97, 0xdd, 0xb9, 0x07, 0x64, 0x94, 0xca, 0x5f,
+			0x81, 0x10, 0x4a, 0x30, 0x5b, 0x6d, 0xd2, 0x76,
+			0x65, 0x72, 0x2c, 0x46, 0xb6, 0x0e, 0x5d, 0xf6,
+			0x80, 0xfb, 0x16, 0xb2, 0x10, 0x60, 0x7e, 0xf2,
+			0x17, 0x65, 0x2e, 0x60, 0x23, 0x6c, 0x25, 0x5f,
+			0x6a, 0x28, 0x31, 0x5f, 0x40, 0x83, 0xa9, 0x67,
+			0x91, 0xd7, 0x21, 0x4b, 0xf6, 0x4c, 0x1d, 0xf4,
+			0xfd, 0x0d, 0xb1, 0x94, 0x4f, 0xb2, 0x6a, 0x2a,
+			0x57, 0x03, 0x1b, 0x32, 0xee, 0xe6, 0x4a, 0xd1,
+			0x5a, 0x8b, 0xa6, 0x88, 0x85, 0xcd, 0xe7, 0x4a,
+			0x5b, 0xfc, 0x92, 0x0f, 0x6a, 0xbf, 0x59, 0xba,
+			0x5c, 0x75, 0x50, 0x63, 0x73, 0xe7, 0x13, 0x0f,
+			0x90, 0x42, 0xda, 0x92, 0x21, 0x79, 0x25, 0x1f,
+		}),
+	}, // Fingerprint: c3b42b026ce86b21
+	{
+		E: 65537,
+		N: new(big.Int).SetBytes([]byte{
+			0xae, 0xec, 0x36, 0xc8, 0xff, 0xc1, 0x09, 0xcb,
+			0x09, 0x96, 0x24, 0x68, 0x5b, 0x97, 0x81, 0x54,
+			0x15, 0x65, 0x7b, 0xd7, 0x6d, 0x8c, 0x9c, 0x3e,
+			0x39, 0x81, 0x03, 0xd7, 0xad, 0x16, 0xc9, 0xbb,
+			0xa6, 0xf5, 0x25, 0xed, 0x04, 0x12, 0xd7, 0xae,
+			0x2c, 0x2d, 0xe2, 0xb4, 0x4e, 0x77, 0xd7, 0x2c,
+			0xbf, 0x4b, 0x74, 0x38, 0x70, 0x9a, 0x4e, 0x64,
+			0x6a, 0x05, 0xc4, 0x34, 0x27, 0xc7, 0xf1, 0x84,
+			0xde, 0xbf, 0x72, 0x94, 0x75, 0x19, 0x68, 0x0e,
+			0x65, 0x15, 0x00, 0x89, 0x0c, 0x68, 0x32, 0x79,
+			0x6d, 0xd1, 0x1f, 0x77, 0x2c, 0x25, 0xff, 0x8f,
+			0x57, 0x67, 0x55, 0xaf, 0xe0, 0x55, 0xb0, 0xa3,
+			0x75, 0x2c, 0x69, 0x6e, 0xb7, 0xd8, 0xda, 0x0d,
+			0x8b, 0xe1, 0xfa, 0xf3, 0x8c, 0x9b, 0xdd, 0x97,
+			0xce, 0x0a, 0x77, 0xd3, 0x91, 0x62, 0x30, 0xc4,
+			0x03, 0x21, 0x67, 0x10, 0x0e, 0xdd, 0x0f, 0x9e,
+			0x7a, 0x3a, 0x9b, 0x60, 0x2d, 0x04, 0x36, 0x7b,
+			0x68, 0x95, 0x36, 0xaf, 0x0d, 0x64, 0xb6, 0x13,
+			0xcc, 0xba, 0x79, 0x62, 0x93, 0x9d, 0x3b, 0x57,
+			0x68, 0x2b, 0xeb, 0x6d, 0xae, 0x5b, 0x60, 0x81,
+			0x30, 0xb2, 0xe5, 0x2a, 0xca, 0x78, 0xba, 0x02,
+			0x3c, 0xf6, 0xce, 0x80, 0x6b, 0x1d, 0xc4, 0x9c,
+			0x72, 0xcf, 0x92, 0x8a, 0x71, 0x99, 0xd2, 0x2e,
+			0x3d, 0x7a, 0xc8, 0x4e, 0x47, 0xbc, 0x94, 0x27,
+			0xd0, 0x23, 0x69, 0x45, 0xd1, 0x0d, 0xbd, 0x15,
+			0x17, 0x7b, 0xab, 0x41, 0x3f, 0xbf, 0x0e, 0xdf,
+			0xda, 0x09, 0xf0, 0x14, 0xc7, 0xa7, 0xda, 0x08,
+			0x8d, 0xde, 0x97, 0x59, 0x70, 0x2c, 0xa7, 0x60,
+			0xaf, 0x2b, 0x8e, 0x4e, 0x97, 0xcc, 0x05, 0x5c,
+			0x61, 0x7b, 0xd7, 0x4c, 0x3d, 0x97, 0x00, 0x86,
+			0x35, 0xb9, 0x8d, 0xc4, 0xd6, 0x21, 0xb4, 0x89,
+			0x1d, 0xa9, 0xfb, 0x04, 0x73, 0x04, 0x79, 0x27,
+		}),
+	}, // Fingerprint: bc35f3509f7b7a5
+	{
+		E: 65537,
+		N: new(big.Int).SetBytes([]byte{
+			0xbd, 0xf2, 0xc7, 0x7d, 0x81, 0xf6, 0xaf, 0xd4,
+			0x7b, 0xd3, 0x0f, 0x29, 0xac, 0x76, 0xe5, 0x5a,
+			0xdf, 0xe7, 0x0e, 0x48, 0x7e, 0x5e, 0x48, 0x29,
+			0x7e, 0x5a, 0x90, 0x55, 0xc9, 0xc0, 0x7d, 0x2b,
+			0x93, 0xb4, 0xed, 0x39, 0x94, 0xd3, 0xec, 0xa5,
+			0x09, 0x8b, 0xf1, 0x8d, 0x97, 0x8d, 0x54, 0xf8,
+			0xb7, 0xc7, 0x13, 0xeb, 0x10, 0x24, 0x76, 0x07,
+			0xe6, 0x9a, 0xf9, 0xef, 0x44, 0xf3, 0x8e, 0x28,
+			0xf8, 0xb4, 0x39, 0xf2, 0x57, 0xa1, 0x15, 0x72,
+			0x94, 0x5c, 0xc0, 0x40, 0x6f, 0xe3, 0xf3, 0x7b,
+			0xb9, 0x2b, 0x79, 0x11, 0x2d, 0xb6, 0x9e, 0xed,
+			0xf2, 0xdc, 0x71, 0x58, 0x4a, 0x66, 0x16, 0x38,
+			0xea, 0x5b, 0xec, 0xb9, 0xe2, 0x35, 0x85, 0x07,
+			0x4b, 0x80, 0xd5, 0x7d, 0x9f, 0x57, 0x10, 0xdd,
+			0x30, 0xd2, 0xda, 0x94, 0x0e, 0x0a, 0xda, 0x2f,
+			0x1b, 0x87, 0x83, 0x97, 0xdc, 0x1a, 0x72, 0xb5,
+			0xce, 0x25, 0x31, 0xb6, 0xf7, 0xdd, 0x15, 0x8e,
+			0x09, 0xc8, 0x28, 0xd0, 0x34, 0x50, 0xca, 0x0f,
+			0xf8, 0xa1, 0x74, 0xde, 0xac, 0xeb, 0xca, 0xa2,
+			0x2d, 0xde, 0x84, 0xef, 0x66, 0xad, 0x37, 0x0f,
+			0x25, 0x9d, 0x18, 0xaf, 0x80, 0x66, 0x38, 0x01,
+			0x2d, 0xa0, 0xca, 0x4a, 0x70, 0xba, 0xa8, 0x3d,
+			0x9c, 0x15, 0x8f, 0x35, 0x52, 0xbc, 0x91, 0x58,
+			0xe6, 0x9b, 0xf3, 0x32, 0xa4, 0x58, 0x09, 0xe1,
+			0xc3, 0x69, 0x05, 0xa5, 0xca, 0xa1, 0x23, 0x48,
+			0xdd, 0x57, 0x94, 0x1a, 0x48, 0x21, 0x31, 0xbe,
+			0x7b, 0x23, 0x55, 0xa5, 0xf4, 0x63, 0x53, 0x74,
+			0xf3, 0xbd, 0x3d, 0xdf, 0x5f, 0xf9, 0x25, 0xbf,
+			0x48, 0x09, 0xee, 0x27, 0xc1, 0xe6, 0x7d, 0x91,
+			0x20, 0xc5, 0xfe, 0x08, 0xa9, 0xde, 0x45, 0x8b,
+			0x1b, 0x4a, 0x3c, 0x5d, 0x0a, 0x42, 0x84, 0x37,
+			0xf2, 0xbe, 0xca, 0x81, 0xf4, 0xe2, 0xd5, 0xff,
+		}),
+	}, // Fingerprint: 15ae5fa8b5529542
+	{
+		E: 65537,
+		N: new(big.Int).SetBytes([]byte{
+			0xb3, 0xf7, 0x62, 0xb7, 0x39, 0xbe, 0x98, 0xf3,
+			0x43, 0xeb, 0x19, 0x21, 0xcf, 0x01, 0x48, 0xcf,
+			0xa2, 0x7f, 0xf7, 0xaf, 0x02, 0xb6, 0x47, 0x12,
+			0x13, 0xfe, 0xd9, 0xda, 0xa0, 0x09, 0x89, 0x76,
+			0xe6, 0x67, 0x75, 0x03, 0x24, 0xf1, 0xab, 0xce,
+			0xa4, 0xc3, 0x1e, 0x43, 0xb7, 0xd1, 0x1f, 0x15,
+			0x79, 0x13, 0x3f, 0x2b, 0x3d, 0x9f, 0xe2, 0x74,
+			0x74, 0xe4, 0x62, 0x05, 0x88, 0x84, 0xe5, 0xe1,
+			0xb1, 0x23, 0xbe, 0x9c, 0xbb, 0xc6, 0xa4, 0x43,
+			0xb2, 0x92, 0x5c, 0x08, 0x52, 0x0e, 0x73, 0x25,
+			0xe6, 0xf1, 0xa6, 0xd5, 0x0e, 0x11, 0x7e, 0xb6,
+			0x1e, 0xa4, 0x9d, 0x25, 0x34, 0xc8, 0xbb, 0x4d,
+			0x2a, 0xe4, 0x15, 0x3f, 0xab, 0xe8, 0x32, 0xb9,
+			0xed, 0xf4, 0xc5, 0x75, 0x5f, 0xdd, 0x8b, 0x19,
+			0x94, 0x0b, 0x81, 0xd1, 0xd9, 0x6c, 0xf4, 0x33,
+			0xd1, 0x9e, 0x6a, 0x22, 0x96, 0x8a, 0x85, 0xdc,
+			0x80, 0xf0, 0x31, 0x2f, 0x59, 0x6b, 0xd2, 0x53,
+			0x0c, 0x1c, 0xfb, 0x28, 0xb5, 0xfe, 0x01, 0x9a,
+			0xc9, 0xbc, 0x25, 0xcd, 0x9c, 0x2a, 0x5d, 0x8a,
+			0x0f, 0x3a, 0x1c, 0x0c, 0x79, 0xbc, 0xca, 0x52,
+			0x4d, 0x31, 0x5b, 0x5e, 0x21, 0xb5, 0xc2, 0x6b,
+			0x46, 0xba, 0xbe, 0x3d, 0x75, 0xd0, 0x6d, 0x1c,
+			0xd3, 0x33, 0x29, 0xec, 0x78, 0x2a, 0x0f, 0x22,
+			0x89, 0x1e, 0xd1, 0xdb, 0x42, 0xa1, 0xd6, 0xc0,
+			0xde, 0xa4, 0x31, 0x42, 0x8b, 0xc4, 0xd7, 0xaa,
+			0xbd, 0xcf, 0x3e, 0x0e, 0xb6, 0xfd, 0xa4, 0xe2,
+			0x3e, 0xb7, 0x73, 0x3e, 0x77, 0x27, 0xe9, 0xa1,
+			0x91, 0x55, 0x80, 0x79, 0x6c, 0x55, 0x18, 0x8d,
+			0x25, 0x96, 0xd2, 0x66, 0x5a, 0xd1, 0x18, 0x2b,
+			0xa7, 0xab, 0xf1, 0x5a, 0xaa, 0x5a, 0x8b, 0x77,
+			0x9e, 0xa9, 0x96, 0x31, 0x7a, 0x20, 0xae, 0x04,
+			0x4b, 0x82, 0x0b, 0xff, 0x35, 0xb6, 0xe8, 0xa1,
+		}),
+	}, // Fingerprint: aeae98e13cd7f94f
+	{
+		E: 65537,
+		N: new(big.Int).SetBytes([]byte{
+			0xbe, 0x6a, 0x71, 0x55, 0x8e, 0xe5, 0x77, 0xff,
+			0x03, 0x02, 0x3c, 0xfa, 0x17, 0xaa, 0xb4, 0xe6,
+			0xc8, 0x63, 0x83, 0xcf, 0xf8, 0xa7, 0xad, 0x38,
+			0xed, 0xb9, 0xfa, 0xfe, 0x6f, 0x32, 0x3f, 0x2d,
+			0x51, 0x06, 0xcb, 0xc8, 0xca, 0xfb, 0x83, 0xb8,
+			0x69, 0xcf, 0xfd, 0x1c, 0xcf, 0x12, 0x1c, 0xd7,
+			0x43, 0xd5, 0x09, 0xe5, 0x89, 0xe6, 0x87, 0x65,
+			0xc9, 0x66, 0x01, 0xe8, 0x13, 0xdc, 0x5b, 0x9d,
+			0xfc, 0x4b, 0xe4, 0x15, 0xc7, 0xa6, 0x52, 0x61,
+			0x32, 0xd0, 0x03, 0x5c, 0xa3, 0x3d, 0x6d, 0x60,
+			0x75, 0xd4, 0xf5, 0x35, 0x12, 0x2a, 0x1c, 0xdf,
+			0xe0, 0x17, 0x04, 0x1f, 0x10, 0x88, 0xd1, 0x41,
+			0x9f, 0x65, 0xc8, 0xe5, 0x49, 0x0e, 0xe6, 0x13,
+			0xe1, 0x6d, 0xbf, 0x66, 0x26, 0x98, 0xc0, 0xf5,
+			0x48, 0x70, 0xf0, 0x47, 0x5f, 0xa8, 0x93, 0xfc,
+			0x41, 0xeb, 0x55, 0xb0, 0x8f, 0xf1, 0xac, 0x21,
+			0x1b, 0xc0, 0x45, 0xde, 0xd3, 0x1b, 0xe2, 0x7d,
+			0x12, 0xc9, 0x6d, 0x8d, 0x3c, 0xfc, 0x6a, 0x7a,
+			0xe8, 0xaa, 0x50, 0xbf, 0x2e, 0xe0, 0xf3, 0x0e,
+			0xd5, 0x07, 0xcc, 0x25, 0x81, 0xe3, 0xde, 0xc5,
+			0x6d, 0xe9, 0x4f, 0x5d, 0xc0, 0xa7, 0xab, 0xee,
+			0x0b, 0xe9, 0x90, 0xb8, 0x93, 0xf2, 0x88, 0x7b,
+			0xd2, 0xc6, 0x31, 0x0a, 0x1e, 0x0a, 0x9e, 0x3e,
+			0x38, 0xbd, 0x34, 0xfd, 0xed, 0x25, 0x41, 0x50,
+			0x8d, 0xc1, 0x02, 0xa9, 0xc9, 0xb4, 0xc9, 0x5e,
+			0xff, 0xd9, 0xdd, 0x2d, 0xfe, 0x96, 0xc2, 0x9b,
+			0xe6, 0x47, 0xd6, 0xc6, 0x9d, 0x66, 0xca, 0x50,
+			0x08, 0x43, 0xcf, 0xae, 0xd6, 0xe4, 0x40, 0x19,
+			0x6f, 0x1d, 0xbe, 0x0e, 0x2e, 0x22, 0x16, 0x3c,
+			0x61, 0xca, 0x48, 0xc7, 0x91, 0x16, 0xfa, 0x77,
+			0x21, 0x67, 0x26, 0x74, 0x9a, 0x97, 0x6a, 0x1c,
+			0x4b, 0x09, 0x44, 0xb5, 0x12, 0x1e, 0x8c, 0x01,
+		}),
+	}, // Fingerprint: 5a181b2235057d98
+}

pkg/gotd/cmd/rsagen/_example/rsagen_many_test.go

@@ -0,0 +1,30 @@
+// Code generated by rsagen, DO NOT EDIT.
+
+package example
+
+import (
+	"crypto/rsa"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/crypto"
+)
+
+func TestFingerprintManyPK(t *testing.T) {
+	fingerprint := func(pubkey *rsa.PublicKey) string {
+		return fmt.Sprintf("%08x", uint64(crypto.RSAFingerprint(pubkey)))
+	}
+	expected := []string{
+		"c3b42b026ce86b21",
+		"bc35f3509f7b7a5",
+		"15ae5fa8b5529542",
+		"aeae98e13cd7f94f",
+		"5a181b2235057d98",
+	}
+	assert.Len(t, ManyPK, len(expected))
+	for i, pubkey := range ManyPK {
+		assert.Equal(t, expected[i], fingerprint(pubkey))
+	}
+}

pkg/gotd/cmd/rsagen/_example/rsagen_single.go

@@ -0,0 +1,58 @@
+// Code generated by rsagen, DO NOT EDIT.
+//
+// -----BEGIN RSA PUBLIC KEY-----
+// MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6
+// lyDONS789sVoD/xCS9Y0hkkC3gtL1tSfTlgCMOOul9lcixlEKzwKENj1Yz/s7daS
+// an9tqw3bfUV/nqgbhGX81v/+7RFAEd+RwFnK7a+XYl9sluzHRyVVaTTveB2GazTw
+// Efzk2DWgkBluml8OREmvfraX3bkHZJTKX4EQSjBbbdJ2ZXIsRrYOXfaA+xayEGB+
+// 8hdlLmAjbCVfaigxX0CDqWeR1yFL9kwd9P0NsZRPsmoqVwMbMu7mStFai6aIhc3n
+// Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
+// -----END RSA PUBLIC KEY-----
+//
+
+package example
+
+import (
+	"crypto/rsa"
+	"math/big"
+)
+
+var _ = (*big.Int)(nil)
+
+var SinglePK = &rsa.PublicKey{
+	E: 65537,
+	N: new(big.Int).SetBytes([]byte{
+		0xc1, 0x50, 0x02, 0x3e, 0x2f, 0x70, 0xdb, 0x79,
+		0x85, 0xde, 0xd0, 0x64, 0x75, 0x9c, 0xfe, 0xcf,
+		0x0a, 0xf3, 0x28, 0xe6, 0x9a, 0x41, 0xda, 0xf4,
+		0xd6, 0xf0, 0x1b, 0x53, 0x81, 0x35, 0xa6, 0xf9,
+		0x1f, 0x8f, 0x8b, 0x2a, 0x0e, 0xc9, 0xba, 0x97,
+		0x20, 0xce, 0x35, 0x2e, 0xfc, 0xf6, 0xc5, 0x68,
+		0x0f, 0xfc, 0x42, 0x4b, 0xd6, 0x34, 0x86, 0x49,
+		0x02, 0xde, 0x0b, 0x4b, 0xd6, 0xd4, 0x9f, 0x4e,
+		0x58, 0x02, 0x30, 0xe3, 0xae, 0x97, 0xd9, 0x5c,
+		0x8b, 0x19, 0x44, 0x2b, 0x3c, 0x0a, 0x10, 0xd8,
+		0xf5, 0x63, 0x3f, 0xec, 0xed, 0xd6, 0x92, 0x6a,
+		0x7f, 0x6d, 0xab, 0x0d, 0xdb, 0x7d, 0x45, 0x7f,
+		0x9e, 0xa8, 0x1b, 0x84, 0x65, 0xfc, 0xd6, 0xff,
+		0xfe, 0xed, 0x11, 0x40, 0x11, 0xdf, 0x91, 0xc0,
+		0x59, 0xca, 0xed, 0xaf, 0x97, 0x62, 0x5f, 0x6c,
+		0x96, 0xec, 0xc7, 0x47, 0x25, 0x55, 0x69, 0x34,
+		0xef, 0x78, 0x1d, 0x86, 0x6b, 0x34, 0xf0, 0x11,
+		0xfc, 0xe4, 0xd8, 0x35, 0xa0, 0x90, 0x19, 0x6e,
+		0x9a, 0x5f, 0x0e, 0x44, 0x49, 0xaf, 0x7e, 0xb6,
+		0x97, 0xdd, 0xb9, 0x07, 0x64, 0x94, 0xca, 0x5f,
+		0x81, 0x10, 0x4a, 0x30, 0x5b, 0x6d, 0xd2, 0x76,
+		0x65, 0x72, 0x2c, 0x46, 0xb6, 0x0e, 0x5d, 0xf6,
+		0x80, 0xfb, 0x16, 0xb2, 0x10, 0x60, 0x7e, 0xf2,
+		0x17, 0x65, 0x2e, 0x60, 0x23, 0x6c, 0x25, 0x5f,
+		0x6a, 0x28, 0x31, 0x5f, 0x40, 0x83, 0xa9, 0x67,
+		0x91, 0xd7, 0x21, 0x4b, 0xf6, 0x4c, 0x1d, 0xf4,
+		0xfd, 0x0d, 0xb1, 0x94, 0x4f, 0xb2, 0x6a, 0x2a,
+		0x57, 0x03, 0x1b, 0x32, 0xee, 0xe6, 0x4a, 0xd1,
+		0x5a, 0x8b, 0xa6, 0x88, 0x85, 0xcd, 0xe7, 0x4a,
+		0x5b, 0xfc, 0x92, 0x0f, 0x6a, 0xbf, 0x59, 0xba,
+		0x5c, 0x75, 0x50, 0x63, 0x73, 0xe7, 0x13, 0x0f,
+		0x90, 0x42, 0xda, 0x92, 0x21, 0x79, 0x25, 0x1f,
+	}),
+} // Fingerprint: c3b42b026ce86b21

pkg/gotd/cmd/rsagen/_example/rsagen_single_test.go

@@ -0,0 +1,20 @@
+// Code generated by rsagen, DO NOT EDIT.
+
+package example
+
+import (
+	"crypto/rsa"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/crypto"
+)
+
+func TestFingerprintSinglePK(t *testing.T) {
+	fingerprint := func(pubkey *rsa.PublicKey) string {
+		return fmt.Sprintf("%08x", uint64(crypto.RSAFingerprint(pubkey)))
+	}
+	assert.Equal(t, "c3b42b026ce86b21", fingerprint(SinglePK))
+}

pkg/gotd/cmd/rsagen/_example/single.pem

@@ -0,0 +1,8 @@
+-----BEGIN RSA PUBLIC KEY-----
+MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6
+lyDONS789sVoD/xCS9Y0hkkC3gtL1tSfTlgCMOOul9lcixlEKzwKENj1Yz/s7daS
+an9tqw3bfUV/nqgbhGX81v/+7RFAEd+RwFnK7a+XYl9sluzHRyVVaTTveB2GazTw
+Efzk2DWgkBluml8OREmvfraX3bkHZJTKX4EQSjBbbdJ2ZXIsRrYOXfaA+xayEGB+
+8hdlLmAjbCVfaigxX0CDqWeR1yFL9kwd9P0NsZRPsmoqVwMbMu7mStFai6aIhc3n
+Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
+-----END RSA PUBLIC KEY-----

pkg/gotd/cmd/rsagen/_template/main.tmpl

@@ -0,0 +1,50 @@
+// Code generated by rsagen, DO NOT EDIT.
+//
+{{ range .InputLines -}}
+// {{ printf "%s" . }}
+{{ end -}}
+//
+
+package {{ .Package }}
+
+import (
+	"crypto/rsa"
+	"math/big"
+)
+
+var _ = (*big.Int)(nil)
+
+{{ define "chunks" -}}
+	{{- range chunks . 8 }}
+		{{ range . }}{{ printf "%#02x" . }},{{ end }}
+	{{- end }}
+{{- end }}
+
+{{ define "bigint-positive" -}}
+	new(big.Int).SetBytes([]byte{
+		{{- template "chunks" .Bytes }}
+	})
+{{- end }}
+
+{{ define "bigint" }}
+	{{- if eq .Sign -1 -}} new(big.Int).Neg( {{- end -}}
+	{{- template "bigint-positive" . -}}
+	{{- if eq .Sign -1 -}} ) {{- end -}}
+{{ end }}
+
+{{ define "pubkey" -}}
+	&rsa.PublicKey{
+		E: {{ .E }},
+		N: {{ template "bigint" .N }},
+	}
+{{- end }}
+
+{{ if not .Single }}
+	var {{ .Variable }} = []*rsa.PublicKey{
+		{{- range .Keys }}
+			{{ template "pubkey" . }}, // Fingerprint: {{ fingerprint . }}
+		{{- end }}
+	}
+{{ else }}
+	var {{ .Variable }} = {{ template "pubkey" (single .Keys) }} // Fingerprint: {{ single .Keys | fingerprint }}
+{{ end }}

pkg/gotd/cmd/rsagen/_template/test.tmpl

@@ -0,0 +1,32 @@
+// Code generated by rsagen, DO NOT EDIT.
+
+package {{ .Package }}
+
+import (
+	"crypto/rsa"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/crypto"
+)
+
+func {{ .TestFunc }}(t *testing.T) {
+	fingerprint := func(pubkey *rsa.PublicKey) string {
+		return fmt.Sprintf("%08x", uint64(crypto.RSAFingerprint(pubkey)))
+	}
+	{{- if .Single }}
+		assert.Equal(t, {{ single .Keys | fingerprint | printf "%q" }}, fingerprint({{ .Variable }}))
+	{{- else }}
+		expected := []string{
+			{{- range .Keys }}
+				{{ fingerprint . | printf "%q" }},
+			{{- end }}
+		}
+		assert.Len(t, {{ .Variable }}, len(expected))
+		for i, pubkey := range {{ .Variable }} {
+			assert.Equal(t, expected[i], fingerprint(pubkey))
+		}
+	{{- end }}
+}

pkg/gotd/cmd/rsagen/main.go

@@ -0,0 +1,147 @@
+// The rsagen command generates rsa.PublicKey variables from PEM-encoded
+// RSA public keys.
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/rsa"
+	"embed"
+	"flag"
+	"fmt"
+	"go/format"
+	"io"
+	"io/fs"
+	"log"
+	"os"
+	"text/template"
+
+	"github.com/go-faster/errors"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/crypto"
+)
+
+//go:embed _template/*.tmpl
+var embedFS embed.FS
+
+var funcs = template.FuncMap{
+	"fingerprint": func(pubkey *rsa.PublicKey) string {
+		return fmt.Sprintf("%08x", uint64(crypto.RSAFingerprint(pubkey)))
+	},
+	"chunks": func(b []byte, size int) [][]byte {
+		var chunks [][]byte
+		for len(b) > size {
+			chunks = append(chunks, b[:size])
+			b = b[size:]
+		}
+		if len(b) != 0 {
+			chunks = append(chunks, b)
+		}
+		return chunks
+	},
+	"single": func(keys []*rsa.PublicKey) (*rsa.PublicKey, error) {
+		if count := len(keys); count != 1 {
+			return nil, errors.Errorf("expected single key, got %d keys", count)
+		}
+		return keys[0], nil
+	},
+}
+
+func main() {
+	if err := run(); err != nil {
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	log.SetFlags(log.Llongfile)
+	var (
+		inPath       = flag.String("f", "", "input path (defaults to stdin)")
+		outPath      = flag.String("o", "", "output path (defaults to stdout)")
+		tplPath      = flag.String("templates", "", "templates directory (defaults to embed)")
+		tplName      = flag.String("exec", "main.tmpl", "template name")
+		pkgName      = flag.String("pkg", "main", "package name")
+		varName      = flag.String("var", "PK", "variable name")
+		singleMode   = flag.Bool("single", false, "emit single key instead of slice")
+		formatOutput = flag.Bool("format", true, "run gofmt on output")
+		testFunc     = flag.String("test", "", "test function name")
+	)
+	flag.Parse()
+
+	if *testFunc == "" {
+		*testFunc = "TestFingerprint" + *varName
+	}
+
+	var err error
+
+	var in []byte
+	if *inPath != "" {
+		in, err = os.ReadFile(*inPath)
+	} else {
+		in, err = io.ReadAll(os.Stdin)
+	}
+	if err != nil {
+		log.Printf("read input: %v", err)
+		return err
+	}
+
+	keys, err := crypto.ParseRSAPublicKeys(in)
+	if err != nil {
+		log.Printf("parse public keys: %v", err)
+		return err
+	}
+
+	fsys, _ := fs.Sub(embedFS, "_template")
+	if *tplPath != "" {
+		fsys = os.DirFS(*tplPath)
+	}
+
+	tpl, err := template.New("").Funcs(funcs).ParseFS(fsys, "*.tmpl")
+	if err != nil {
+		log.Printf("parse templates: %v", err)
+		return err
+	}
+
+	var inLines [][]byte
+	for sc := bufio.NewScanner(bytes.NewReader(in)); sc.Scan(); {
+		line := sc.Bytes()
+		line = bytes.TrimSpace(line)
+		if len(line) == 0 {
+			continue
+		}
+		inLines = append(inLines, line)
+	}
+
+	buf := bytes.NewBuffer(nil)
+	if err := tpl.ExecuteTemplate(buf, *tplName, map[string]interface{}{
+		"Package":    *pkgName,
+		"Variable":   *varName,
+		"Keys":       keys,
+		"Single":     *singleMode,
+		"InputLines": inLines,
+		"TestFunc":   *testFunc,
+	}); err != nil {
+		log.Printf("execute template: %v", err)
+		return err
+	}
+
+	if *formatOutput {
+		p, err := format.Source(buf.Bytes())
+		if err != nil {
+			log.Printf("format output: %v", err)
+			return err
+		}
+		buf = bytes.NewBuffer(p)
+	}
+
+	if *outPath != "" {
+		err = os.WriteFile(*outPath, buf.Bytes(), 0o600)
+	} else {
+		_, err = buf.WriteTo(os.Stdout)
+	}
+	if err != nil {
+		log.Printf("write output: %v", err)
+		return err
+	}
+	return nil
+}

pkg/gotd/cmd/rsagen/main_test.go

@@ -0,0 +1,27 @@
+//go:build linux
+
+package main
+
+import (
+	"os"
+	"testing"
+
+	"github.com/rogpeppe/go-internal/testscript"
+)
+
+func TestMain(m *testing.M) {
+	os.Exit(testscript.RunMain(m, map[string]func() int{
+		"rsagen": func() int {
+			if err := run(); err != nil {
+				return 1
+			}
+			return 0
+		},
+	}))
+}
+
+func TestScript(t *testing.T) {
+	testscript.Run(t, testscript.Params{
+		Dir: "testdata",
+	})
+}

pkg/gotd/cmd/rsagen/testdata/format.txt

@@ -0,0 +1,12 @@
+# Shows format error
+! rsagen -templates template
+! stdout .
+stderr 'format output: '
+
+# Disables formatting
+rsagen -format=false -templates template
+cmp stdout template/main.tmpl
+! stderr .
+
+-- template/main.tmpl --
+/* unclosed comment

pkg/gotd/cmd/rsagen/testdata/input.txt

@@ -0,0 +1,20 @@
+# Reads from file
+rsagen -f input.pem
+! stderr .
+stdout -count=1 '// Fingerprint:'
+stdout '// Fingerprint: c3b42b026ce86b21'
+
+# Error on non-existent file
+! rsagen -f missing.pem
+! stdout .
+stderr 'read input: '
+
+-- input.pem --
+-----BEGIN RSA PUBLIC KEY-----
+MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6
+lyDONS789sVoD/xCS9Y0hkkC3gtL1tSfTlgCMOOul9lcixlEKzwKENj1Yz/s7daS
+an9tqw3bfUV/nqgbhGX81v/+7RFAEd+RwFnK7a+XYl9sluzHRyVVaTTveB2GazTw
+Efzk2DWgkBluml8OREmvfraX3bkHZJTKX4EQSjBbbdJ2ZXIsRrYOXfaA+xayEGB+
+8hdlLmAjbCVfaigxX0CDqWeR1yFL9kwd9P0NsZRPsmoqVwMbMu7mStFai6aIhc3n
+Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
+-----END RSA PUBLIC KEY-----

pkg/gotd/cmd/rsagen/testdata/many.txt

@@ -0,0 +1,78 @@
+# OK on empty
+rsagen
+! stderr .
+stdout '\[]\*rsa.PublicKey\{}'
+
+# OK on single key
+stdin single.pem
+rsagen
+! stderr .
+stdout -count=1 '// Fingerprint:'
+stdout '// Fingerprint: c3b42b026ce86b21'
+
+# OK on multiple keys
+stdin many.pem
+rsagen
+! stderr .
+stdout -count=5 '// Fingerprint:'
+stdout '// Fingerprint: c3b42b026ce86b21'
+stdout '// Fingerprint: bc35f3509f7b7a5'
+stdout '// Fingerprint: 15ae5fa8b5529542'
+stdout '// Fingerprint: aeae98e13cd7f94f'
+stdout '// Fingerprint: 5a181b2235057d98'
+
+-- single.pem --
+-----BEGIN RSA PUBLIC KEY-----
+MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6
+lyDONS789sVoD/xCS9Y0hkkC3gtL1tSfTlgCMOOul9lcixlEKzwKENj1Yz/s7daS
+an9tqw3bfUV/nqgbhGX81v/+7RFAEd+RwFnK7a+XYl9sluzHRyVVaTTveB2GazTw
+Efzk2DWgkBluml8OREmvfraX3bkHZJTKX4EQSjBbbdJ2ZXIsRrYOXfaA+xayEGB+
+8hdlLmAjbCVfaigxX0CDqWeR1yFL9kwd9P0NsZRPsmoqVwMbMu7mStFai6aIhc3n
+Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
+-----END RSA PUBLIC KEY-----
+
+-- many.pem --
+-----BEGIN RSA PUBLIC KEY-----
+MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6
+lyDONS789sVoD/xCS9Y0hkkC3gtL1tSfTlgCMOOul9lcixlEKzwKENj1Yz/s7daS
+an9tqw3bfUV/nqgbhGX81v/+7RFAEd+RwFnK7a+XYl9sluzHRyVVaTTveB2GazTw
+Efzk2DWgkBluml8OREmvfraX3bkHZJTKX4EQSjBbbdJ2ZXIsRrYOXfaA+xayEGB+
+8hdlLmAjbCVfaigxX0CDqWeR1yFL9kwd9P0NsZRPsmoqVwMbMu7mStFai6aIhc3n
+Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
+-----END RSA PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAruw2yP/BCcsJliRoW5eB
+VBVle9dtjJw+OYED160Wybum9SXtBBLXriwt4rROd9csv0t0OHCaTmRqBcQ0J8fx
+hN6/cpR1GWgOZRUAiQxoMnlt0R93LCX/j1dnVa/gVbCjdSxpbrfY2g2L4frzjJvd
+l84Kd9ORYjDEAyFnEA7dD556OptgLQQ2e2iVNq8NZLYTzLp5YpOdO1doK+ttrltg
+gTCy5SrKeLoCPPbOgGsdxJxyz5KKcZnSLj16yE5HvJQn0CNpRdENvRUXe6tBP78O
+39oJ8BTHp9oIjd6XWXAsp2CvK45Ol8wFXGF710w9lwCGNbmNxNYhtIkdqfsEcwR5
+JwIDAQAB
+-----END PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvfLHfYH2r9R70w8prHbl
+Wt/nDkh+XkgpflqQVcnAfSuTtO05lNPspQmL8Y2XjVT4t8cT6xAkdgfmmvnvRPOO
+KPi0OfJXoRVylFzAQG/j83u5K3kRLbae7fLccVhKZhY46lvsueI1hQdLgNV9n1cQ
+3TDS2pQOCtovG4eDl9wacrXOJTG2990VjgnIKNA0UMoP+KF03qzryqIt3oTvZq03
+DyWdGK+AZjgBLaDKSnC6qD2cFY81UryRWOab8zKkWAnhw2kFpcqhI0jdV5QaSCEx
+vnsjVaX0Y1N0870931/5Jb9ICe4nweZ9kSDF/gip3kWLG0o8XQpChDfyvsqB9OLV
+/wIDAQAB
+-----END PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAs/ditzm+mPND6xkhzwFI
+z6J/968CtkcSE/7Z2qAJiXbmZ3UDJPGrzqTDHkO30R8VeRM/Kz2f4nR05GIFiITl
+4bEjvpy7xqRDspJcCFIOcyXm8abVDhF+th6knSU0yLtNKuQVP6voMrnt9MV1X92L
+GZQLgdHZbPQz0Z5qIpaKhdyA8DEvWWvSUwwc+yi1/gGaybwlzZwqXYoPOhwMebzK
+Uk0xW14htcJrRrq+PXXQbRzTMynseCoPIoke0dtCodbA3qQxQovE16q9zz4Otv2k
+4j63cz53J+mhkVWAeWxVGI0lltJmWtEYK6er8VqqWot3nqmWMXogrgRLggv/Nbbo
+oQIDAQAB
+-----END PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvmpxVY7ld/8DAjz6F6q0
+5shjg8/4p6047bn6/m8yPy1RBsvIyvuDuGnP/RzPEhzXQ9UJ5Ynmh2XJZgHoE9xb
+nfxL5BXHplJhMtADXKM9bWB11PU1Eioc3+AXBB8QiNFBn2XI5UkO5hPhbb9mJpjA
+9Uhw8EdfqJP8QetVsI/xrCEbwEXe0xvifRLJbY08/Gp66KpQvy7g8w7VB8wlgePe
+xW3pT13Ap6vuC+mQuJPyiHvSxjEKHgqePji9NP3tJUFQjcECqcm0yV7/2d0t/pbC
+m+ZH1sadZspQCEPPrtbkQBlvHb4OLiIWPGHKSMeRFvp3IWcmdJqXahxLCUS1Eh6M
+AQIDAQAB
+-----END PUBLIC KEY-----

pkg/gotd/cmd/rsagen/testdata/output.txt

@@ -0,0 +1,11 @@
+# Can output to filesystem
+rsagen -o out.go
+! stderr .
+! stdout .
+grep '\[]\*rsa.PublicKey\{}' out.go
+
+# Error on writing to directory
+mkdir dir
+! rsagen -o dir
+! stdout .
+stderr 'write output: '

pkg/gotd/cmd/rsagen/testdata/rsa.txt

@@ -0,0 +1,13 @@
+! rsagen -f shirou.pem
+! stdout .
+stderr 'parse public keys: '
+
+-- shirou.pem --
+-----BEGIN RSA PUBLIC KEY-----
+SSBhbSB0aGUgYm9uZSBvZiBteSBzd29yZC4KU3RlZWwgaXMgbXkgYm9keSBhbmQg
+ZmlyZSBpcyBteSBibG9vZC4KSSBoYXZlIGNyZWF0ZWQgb3ZlciBhIHRob3VzYW5k
+IGJsYWRlcy4KVW5hd2FyZSBvZiBsb3NzLApOb3IgYXdhcmUgb2YgZ2Fpbi4KV2l0
+aHN0b29kIHBhaW4gdG8gY3JlYXRlIHdlYXBvbnMsIHdhaXRpbmcgZm9yIG9uZeKA
+mXMgYXJyaXZhbC4KSSBoYXZlIG5vIHJlZ3JldHMuIFRoaXMgaXMgdGhlIG9ubHkg
+cGF0aC4KTXkgd2hvbGUgbGlmZSB3YXMgVW5saW1pdGVkIEJsYWRlIFdvcmtzLgo=
+-----END RSA PUBLIC KEY-----

pkg/gotd/cmd/rsagen/testdata/single.txt

@@ -0,0 +1,76 @@
+# OK on single key.
+#
+stdin single.pem
+rsagen -single
+! stderr .
+stdout -count=1 '// Fingerprint:'
+stdout '// Fingerprint: c3b42b026ce86b21'
+
+# Fail on empty input.
+#
+! rsagen -single
+! stdout .
+stderr 'expected single key, got 0 keys'
+
+# Fail on multiple keys.
+#
+stdin many.pem
+! rsagen -single
+! stdout .
+stderr 'expected single key, got 5 keys'
+
+-- single.pem --
+-----BEGIN RSA PUBLIC KEY-----
+MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6
+lyDONS789sVoD/xCS9Y0hkkC3gtL1tSfTlgCMOOul9lcixlEKzwKENj1Yz/s7daS
+an9tqw3bfUV/nqgbhGX81v/+7RFAEd+RwFnK7a+XYl9sluzHRyVVaTTveB2GazTw
+Efzk2DWgkBluml8OREmvfraX3bkHZJTKX4EQSjBbbdJ2ZXIsRrYOXfaA+xayEGB+
+8hdlLmAjbCVfaigxX0CDqWeR1yFL9kwd9P0NsZRPsmoqVwMbMu7mStFai6aIhc3n
+Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
+-----END RSA PUBLIC KEY-----
+
+-- many.pem --
+-----BEGIN RSA PUBLIC KEY-----
+MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6
+lyDONS789sVoD/xCS9Y0hkkC3gtL1tSfTlgCMOOul9lcixlEKzwKENj1Yz/s7daS
+an9tqw3bfUV/nqgbhGX81v/+7RFAEd+RwFnK7a+XYl9sluzHRyVVaTTveB2GazTw
+Efzk2DWgkBluml8OREmvfraX3bkHZJTKX4EQSjBbbdJ2ZXIsRrYOXfaA+xayEGB+
+8hdlLmAjbCVfaigxX0CDqWeR1yFL9kwd9P0NsZRPsmoqVwMbMu7mStFai6aIhc3n
+Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
+-----END RSA PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAruw2yP/BCcsJliRoW5eB
+VBVle9dtjJw+OYED160Wybum9SXtBBLXriwt4rROd9csv0t0OHCaTmRqBcQ0J8fx
+hN6/cpR1GWgOZRUAiQxoMnlt0R93LCX/j1dnVa/gVbCjdSxpbrfY2g2L4frzjJvd
+l84Kd9ORYjDEAyFnEA7dD556OptgLQQ2e2iVNq8NZLYTzLp5YpOdO1doK+ttrltg
+gTCy5SrKeLoCPPbOgGsdxJxyz5KKcZnSLj16yE5HvJQn0CNpRdENvRUXe6tBP78O
+39oJ8BTHp9oIjd6XWXAsp2CvK45Ol8wFXGF710w9lwCGNbmNxNYhtIkdqfsEcwR5
+JwIDAQAB
+-----END PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvfLHfYH2r9R70w8prHbl
+Wt/nDkh+XkgpflqQVcnAfSuTtO05lNPspQmL8Y2XjVT4t8cT6xAkdgfmmvnvRPOO
+KPi0OfJXoRVylFzAQG/j83u5K3kRLbae7fLccVhKZhY46lvsueI1hQdLgNV9n1cQ
+3TDS2pQOCtovG4eDl9wacrXOJTG2990VjgnIKNA0UMoP+KF03qzryqIt3oTvZq03
+DyWdGK+AZjgBLaDKSnC6qD2cFY81UryRWOab8zKkWAnhw2kFpcqhI0jdV5QaSCEx
+vnsjVaX0Y1N0870931/5Jb9ICe4nweZ9kSDF/gip3kWLG0o8XQpChDfyvsqB9OLV
+/wIDAQAB
+-----END PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAs/ditzm+mPND6xkhzwFI
+z6J/968CtkcSE/7Z2qAJiXbmZ3UDJPGrzqTDHkO30R8VeRM/Kz2f4nR05GIFiITl
+4bEjvpy7xqRDspJcCFIOcyXm8abVDhF+th6knSU0yLtNKuQVP6voMrnt9MV1X92L
+GZQLgdHZbPQz0Z5qIpaKhdyA8DEvWWvSUwwc+yi1/gGaybwlzZwqXYoPOhwMebzK
+Uk0xW14htcJrRrq+PXXQbRzTMynseCoPIoke0dtCodbA3qQxQovE16q9zz4Otv2k
+4j63cz53J+mhkVWAeWxVGI0lltJmWtEYK6er8VqqWot3nqmWMXogrgRLggv/Nbbo
+oQIDAQAB
+-----END PUBLIC KEY-----
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvmpxVY7ld/8DAjz6F6q0
+5shjg8/4p6047bn6/m8yPy1RBsvIyvuDuGnP/RzPEhzXQ9UJ5Ynmh2XJZgHoE9xb
+nfxL5BXHplJhMtADXKM9bWB11PU1Eioc3+AXBB8QiNFBn2XI5UkO5hPhbb9mJpjA
+9Uhw8EdfqJP8QetVsI/xrCEbwEXe0xvifRLJbY08/Gp66KpQvy7g8w7VB8wlgePe
+xW3pT13Ap6vuC+mQuJPyiHvSxjEKHgqePji9NP3tJUFQjcECqcm0yV7/2d0t/pbC
+m+ZH1sadZspQCEPPrtbkQBlvHb4OLiIWPGHKSMeRFvp3IWcmdJqXahxLCUS1Eh6M
+AQIDAQAB
+-----END PUBLIC KEY-----

pkg/gotd/cmd/rsagen/testdata/template.txt

@@ -0,0 +1,25 @@
+# Accepts custom templates
+rsagen -format=false -templates good
+stdout sentinel
+! stderr .
+
+# Parse error on invalid template
+! rsagen -format=false -templates bad
+! stdout .
+stderr 'parse templates: '
+
+# Accepts root template name
+rsagen -format=false -templates root -exec root
+stdout tutturu
+! stderr .
+
+-- good/main.tmpl --
+sentinel
+
+-- bad/main.tmpl --
+{{ undefined }}
+
+-- root/root.tmpl --
+{{- define "root" -}}
+tutturu
+{{- end -}}