add OSC 52 clipboard support for terminal applications

frontend/app/view/term/termwrap.ts

@@ -35,6 +35,7 @@ const dlog = debug("wave:termwrap");
 const TermFileName = "term";
 const TermCacheFileName = "cache:term:full";
 const MinDataProcessedForCache = 100 * 1024;
+const Osc52MaxDecodedSize = 75 * 1024; // max clipboard size for OSC 52 (matches common terminal implementations)
 export const SupportsImageInput = true;
 
 // detect webgl support
@@ -119,6 +120,74 @@ function handleOscWaveCommand(data: string, blockId: string, loaded: boolean): b
     return true;
 }
 
+// for xterm OSC handlers, we return true always because we "own" the OSC number.
+// even if data is invalid we don't want to propagate to other handlers.
+function handleOsc52Command(data: string, blockId: string, loaded: boolean): boolean {
+    if (!loaded) {
+        return true;
+    }
+    if (!data || data.length === 0) {
+        console.log("OSC 52: empty data received");
+        return true;
+    }
+
+    const semicolonIndex = data.indexOf(";");
+    if (semicolonIndex === -1) {
+        console.log("OSC 52: invalid format (no semicolon)", data.substring(0, 50));
+        return true;
+    }
+
+    const clipboardSelection = data.substring(0, semicolonIndex);
+    const base64Data = data.substring(semicolonIndex + 1);
+
+    // clipboard query ("?") is not supported for security (prevents clipboard theft)
+    if (base64Data === "?") {
+        console.log("OSC 52: clipboard query not supported");
+        return true;
+    }
+
+    if (base64Data.length === 0) {
+        return true;
+    }
+
+    if (clipboardSelection.length > 10) {
+        console.log("OSC 52: clipboard selection too long", clipboardSelection);
+        return true;
+    }
+
+    const estimatedDecodedSize = Math.ceil(base64Data.length * 0.75);
+    if (estimatedDecodedSize > Osc52MaxDecodedSize) {
+        console.log("OSC 52: data too large", estimatedDecodedSize, "bytes");
+        return true;
+    }
+
+    try {
+        // strip whitespace from base64 data (some terminals chunk with newlines per RFC 4648)
+        const cleanBase64Data = base64Data.replace(/\s+/g, "");
+        const decodedText = base64ToString(cleanBase64Data);
+
+        // validate actual decoded size (base64 estimate can be off for multi-byte UTF-8)
+        const actualByteSize = new TextEncoder().encode(decodedText).length;
+        if (actualByteSize > Osc52MaxDecodedSize) {
+            console.log("OSC 52: decoded text too large", actualByteSize, "bytes");
+            return true;
+        }
+
+        fireAndForget(async () => {
+            try {
+                await navigator.clipboard.writeText(decodedText);
+                dlog("OSC 52: copied", decodedText.length, "characters to clipboard");
+            } catch (err) {
+                console.error("OSC 52: clipboard write failed:", err);
+            }
+        });
+    } catch (e) {
+        console.error("OSC 52: base64 decode error:", e);
+    }
+
+    return true;
+}
+
 // for xterm handlers, we return true always because we "own" OSC 7.
 // even if it is invalid we dont want to propagate to other handlers
 function handleOsc7Command(data: string, blockId: string, loaded: boolean): boolean {
@@ -457,13 +526,16 @@ export class TermWrap {
                 loggedWebGL = true;
             }
         }
-        // Register OSC 9283 handler
-        this.terminal.parser.registerOscHandler(9283, (data: string) => {
-            return handleOscWaveCommand(data, this.blockId, this.loaded);
-        });
+        // Register OSC handlers
         this.terminal.parser.registerOscHandler(7, (data: string) => {
             return handleOsc7Command(data, this.blockId, this.loaded);
         });
+        this.terminal.parser.registerOscHandler(52, (data: string) => {
+            return handleOsc52Command(data, this.blockId, this.loaded);
+        });
+        this.terminal.parser.registerOscHandler(9283, (data: string) => {
+            return handleOscWaveCommand(data, this.blockId, this.loaded);
+        });
         this.terminal.parser.registerOscHandler(16162, (data: string) => {
             return handleOsc16162Command(data, this.blockId, this.loaded, this);
         });

pkg/web/web.go

@@ -5,7 +5,6 @@ package web
 
 import (
 	"bytes"
-	"context"
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
@@ -255,7 +254,7 @@ func handleRemoteStreamFile(w http.ResponseWriter, req *http.Request, conn strin
 	return handleRemoteStreamFileFromCh(w, req, path, rtnCh, rpcOpts.StreamCancelFn, no404)
 }
 
-func handleRemoteStreamFileFromCh(w http.ResponseWriter, req *http.Request, path string, rtnCh <-chan wshrpc.RespOrErrorUnion[wshrpc.FileData], streamCancelFn func(context.Context) error, no404 bool) error {
+func handleRemoteStreamFileFromCh(w http.ResponseWriter, req *http.Request, path string, rtnCh <-chan wshrpc.RespOrErrorUnion[wshrpc.FileData], streamCancelFn func(), no404 bool) error {
 	firstPk := true
 	var fileInfo *wshrpc.FileInfo
 	loopDone := false
@@ -271,9 +270,7 @@ func handleRemoteStreamFileFromCh(w http.ResponseWriter, req *http.Request, path
 		select {
 		case <-ctx.Done():
 			if streamCancelFn != nil {
-				ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-				defer cancel()
-				streamCancelFn(ctx)
+				streamCancelFn()
 			}
 			return ctx.Err()
 		case respUnion, ok := <-rtnCh:

pkg/wshrpc/wshclient/wshclientutil.go

@@ -63,8 +63,8 @@ func sendRpcRequestResponseStreamHelper[T any](w *wshutil.WshRpc, command string
 		rtnErr(respChan, err)
 		return respChan
 	}
-	opts.StreamCancelFn = func(ctx context.Context) error {
-		return reqHandler.SendCancel(ctx)
+	opts.StreamCancelFn = func() {
+		reqHandler.SendCancel(context.Background())
 	}
 	go func() {
 		defer func() {