From abb0ffe5d090094cda9ab0bf38caf22ea57511c3 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Tue, 6 Oct 2020 14:20:28 +0100
Subject: [PATCH] Add furl

---
 cmd/furl/main.go | 97 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 cmd/furl/main.go

diff --git a/cmd/furl/main.go b/cmd/furl/main.go
new file mode 100644
index 000000000..4ad775c5a
--- /dev/null
+++ b/cmd/furl/main.go
@@ -0,0 +1,97 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"crypto/ed25519"
+	"encoding/json"
+	"encoding/pem"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"net/url"
+	"os"
+
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+var requestFrom = flag.String("from", "", "the server name that the request should originate from")
+var requestKey = flag.String("key", "matrix_key.pem", "the private key to use when signing the request")
+
+func main() {
+	flag.Parse()
+
+	if requestFrom == nil || *requestFrom == "" {
+		fmt.Println("expecting: furl -from ... [-key matrix_key.pem] https://path/to/url")
+		fmt.Println("supported flags:")
+		flag.PrintDefaults()
+		os.Exit(1)
+	}
+
+	data, err := ioutil.ReadFile(*requestKey)
+	if err != nil {
+		panic(err)
+	}
+
+	var privateKey ed25519.PrivateKey
+	keyBlock, _ := pem.Decode(data)
+	if keyBlock == nil {
+		panic("keyBlock is nil")
+	}
+	if keyBlock.Type == "MATRIX PRIVATE KEY" {
+		_, privateKey, err = ed25519.GenerateKey(bytes.NewReader(keyBlock.Bytes))
+		if err != nil {
+			panic(err)
+		}
+	} else {
+		panic("unexpected key block")
+	}
+
+	client := gomatrixserverlib.NewFederationClient(
+		gomatrixserverlib.ServerName(*requestFrom),
+		gomatrixserverlib.KeyID(keyBlock.Headers["Key-ID"]),
+		privateKey,
+		false,
+	)
+
+	u, err := url.Parse(flag.Arg(0))
+	if err != nil {
+		panic(err)
+	}
+
+	req := gomatrixserverlib.NewFederationRequest(
+		"GET",
+		gomatrixserverlib.ServerName(u.Host),
+		u.RequestURI(),
+	)
+
+	if err = req.Sign(
+		gomatrixserverlib.ServerName(*requestFrom),
+		gomatrixserverlib.KeyID(keyBlock.Headers["Key-ID"]),
+		privateKey,
+	); err != nil {
+		panic(err)
+	}
+
+	httpReq, err := req.HTTPRequest()
+	if err != nil {
+		panic(err)
+	}
+
+	var res interface{}
+	err = client.DoRequestAndParseResponse(
+		context.TODO(),
+		httpReq,
+		&res,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	j, err := json.MarshalIndent(res, "", "  ")
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(string(j))
+}