http-client: fix base64 decoding of journal content

The grpc gateway returns journal content as a base64-encoded string.
Previously, we had been using `atob` to decode this, but that function
does not work if the decoded content contains any byte values larger
than 0x7f, because of course we can't have nice things in JS. So this
adds one of those looks-insane-but-actually-works workarounds to make
base64 decoding work properly with arbitrary utf-8 data.

Author: psFried

Diff for: client/dist/esm/streams.js

@@ -50,7 +50,17 @@ export function decodeContent() {
         transform(value, controller) {
             // Base64 decode the `content` field and send it as a chunk.
             if (value.content?.length) {
-                controller.enqueue(atob(value.content));
+                // The `atob` function does not work properly if the decoded content contains any byte
+                // values over 0x7f, because "binary" in JS means that each byte gets represented as a
+                // UTF-16 code unit, which happens to be <= 0xff. I wish I was making this up:
+                // https://developer.mozilla.org/en-US/docs/Glossary/Base64#the_unicode_problem
+                const binary = atob(value.content);
+                const bytes = new Uint8Array(binary.length);
+                for (let i = 0; i < bytes.length; i++) {
+                    bytes[i] = binary.charCodeAt(i);
+                }
+                const text = new TextDecoder().decode(bytes);
+                controller.enqueue(text);
             }
         },
     });

Diff for: client/dist/script/streams.js

@@ -56,7 +56,17 @@ function decodeContent() {
         transform(value, controller) {
             // Base64 decode the `content` field and send it as a chunk.
             if (value.content?.length) {
-                controller.enqueue(atob(value.content));
+                // The `atob` function does not work properly if the decoded content contains any byte
+                // values over 0x7f, because "binary" in JS means that each byte gets represented as a
+                // UTF-16 code unit, which happens to be <= 0xff. I wish I was making this up:
+                // https://developer.mozilla.org/en-US/docs/Glossary/Base64#the_unicode_problem
+                const binary = atob(value.content);
+                const bytes = new Uint8Array(binary.length);
+                for (let i = 0; i < bytes.length; i++) {
+                    bytes[i] = binary.charCodeAt(i);
+                }
+                const text = new TextDecoder().decode(bytes);
+                controller.enqueue(text);
             }
         },
     });

Diff for: client/dist/src/streams.ts

@@ -54,7 +54,17 @@ export function decodeContent() {
     transform(value, controller) {
       // Base64 decode the `content` field and send it as a chunk.
       if (value.content?.length) {
-        controller.enqueue(atob(value.content));
+        // The `atob` function does not work properly if the decoded content contains any byte
+        // values over 0x7f, because "binary" in JS means that each byte gets represented as a
+        // UTF-16 code unit, which happens to be <= 0xff. I wish I was making this up:
+        // https://developer.mozilla.org/en-US/docs/Glossary/Base64#the_unicode_problem
+        const binary = atob(value.content);
+        const bytes = new Uint8Array(binary.length);
+        for (let i = 0; i < bytes.length; i++) {
+          bytes[i] = binary.charCodeAt(i);
+        }
+        const text = new TextDecoder().decode(bytes);
+        controller.enqueue(text);
       }
     },
   });

Diff for: client/src/streams.ts

@@ -54,7 +54,17 @@ export function decodeContent() {
     transform(value, controller) {
       // Base64 decode the `content` field and send it as a chunk.
       if (value.content?.length) {
-        controller.enqueue(atob(value.content));
+        // The `atob` function does not work properly if the decoded content contains any byte
+        // values over 0x7f, because "binary" in JS means that each byte gets represented as a
+        // UTF-16 code unit, which happens to be <= 0xff. I wish I was making this up:
+        // https://developer.mozilla.org/en-US/docs/Glossary/Base64#the_unicode_problem
+        const binary = atob(value.content);
+        const bytes = new Uint8Array(binary.length);
+        for (let i = 0; i < bytes.length; i++) {
+          bytes[i] = binary.charCodeAt(i);
+        }
+        const text = new TextDecoder().decode(bytes);
+        controller.enqueue(text);
       }
     },
   });