fix: correctly returns xhr errors when type is blob

fix issue #555

Author: ACTCD

xcode/Safari-Extension/Resources/background.js

@@ -414,18 +414,21 @@ function handleMessage(request, sender, sendResponse) {
                     if (["", "text"].indexOf(xhr.responseType) !== -1) {
                         x.responseText = xhr.responseText;
                     }
-                    // need to convert arraybuffer data to postMessage
-                    if (xhr.responseType === "arraybuffer") {
-                        const arr = Array.from(new Uint8Array(xhr.response));
-                        x.response = arr;
-                    }
-                    // need to blob arraybuffer data to postMessage
-                    if (xhr.responseType === "blob") {
-                        const base64data = await readAsDataURL(xhr.response);
-                        x.response = {
-                            data: base64data,
-                            type: xhr.responseType
-                        };
+                    // only process when xhr is complete and data exist
+                    if (xhr.readyState === 4 && xhr.response !== null) {
+                        // need to convert arraybuffer data to postMessage
+                        if (xhr.responseType === "arraybuffer") {
+                            const arr = Array.from(new Uint8Array(xhr.response));
+                            x.response = arr;
+                        }
+                        // need to convert blob data to postMessage
+                        if (xhr.responseType === "blob") {
+                            const base64data = await readAsDataURL(xhr.response);
+                            x.response = {
+                                data: base64data,
+                                type: xhr.responseType
+                            };
+                        }
                     }
                     port.postMessage({name: e, event, response: x});
                 };

xcode/Safari-Extension/Resources/content.js

@@ -160,21 +160,24 @@ const apis = {
                 ) {
                     // process xhr response
                     const r = msg.response;
-                    if (r.responseType === "arraybuffer") {
-                        // arraybuffer responses had their data converted in background
-                        // convert it back to arraybuffer
-                        try {
-                            const buffer = new Uint8Array(r.response).buffer;
-                            r.response = buffer;
-                        } catch (err) {
-                            console.error("error parsing xhr arraybuffer", err);
+                    // only process when xhr is complete and data exist
+                    if (r.readyState === 4 && r.response !== null) {
+                        if (r.responseType === "arraybuffer") {
+                            // arraybuffer responses had their data converted in background
+                            // convert it back to arraybuffer
+                            try {
+                                const buffer = new Uint8Array(r.response).buffer;
+                                r.response = buffer;
+                            } catch (err) {
+                                console.error("error parsing xhr arraybuffer", err);
+                            }
+                        } else if (r.responseType === "blob" && r.response.data) {
+                            // blob responses had their data converted in background
+                            // convert it back to blob
+                            const resp = await fetch(r.response.data);
+                            const b = await resp.blob();
+                            r.response = b;
                         }
-                    } else if (r.responseType === "blob" && r.response.data) {
-                        // blob responses had their data converted in background
-                        // convert it back to blob
-                        const resp = await fetch(r.response.data);
-                        const b = await resp.blob();
-                        r.response = b;
                     }
                     // call userscript method
                     details[msg.name](msg.response);