Fix HTTP chunked encoding handling

Fixes #151

Update `PEAR/REST.php` and `PEAR/Downloader.php` to handle HTTP chunked encoding responses properly.

---

For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/pear/pear-core/issues/151?shareId=XXXX-XXXX-XXXX-XXXX).

Author: zhangyoufu

PEAR/Downloader.php

@@ -1726,19 +1726,43 @@ public static function _downloadHttp(
             call_user_func($callback, 'start', array(basename($dest_file), $length));
         }
 
-        while ($data = fread($fp, 1024)) {
-            $bytes += strlen($data);
-            if ($callback) {
-                call_user_func($callback, 'bytesread', $bytes);
+        if (isset($headers['transfer-encoding']) && strtolower($headers['transfer-encoding']) === 'chunked') {
+            while (!feof($fp)) {
+                $chunk_size = hexdec(fgets($fp));
+                if ($chunk_size === 0) {
+                    break;
+                }
+                $data = fread($fp, $chunk_size);
+                $bytes += strlen($data);
+                if ($callback) {
+                    call_user_func($callback, 'bytesread', $bytes);
+                }
+                if (!@fwrite($wp, $data)) {
+                    fclose($fp);
+                    if ($callback) {
+                        call_user_func($callback, 'writefailed',
+                            array($dest_file, error_get_last()["message"]));
+                    }
+                    return PEAR::raiseError(
+                        "$dest_file: write failed (" . error_get_last()["message"] . ")");
+                }
+                fgets($fp); // Skip the trailing CRLF
             }
-            if (!@fwrite($wp, $data)) {
-                fclose($fp);
+        } else {
+            while ($data = fread($fp, 1024)) {
+                $bytes += strlen($data);
                 if ($callback) {
-                    call_user_func($callback, 'writefailed',
-                        array($dest_file, error_get_last()["message"]));
+                    call_user_func($callback, 'bytesread', $bytes);
+                }
+                if (!@fwrite($wp, $data)) {
+                    fclose($fp);
+                    if ($callback) {
+                        call_user_func($callback, 'writefailed',
+                            array($dest_file, error_get_last()["message"]));
+                    }
+                    return PEAR::raiseError(
+                        "$dest_file: write failed (" . error_get_last()["message"] . ")");
                 }
-                return PEAR::raiseError(
-                    "$dest_file: write failed (" . error_get_last()["message"] . ")");
             }
         }
 

PEAR/REST.php

@@ -448,8 +448,19 @@ function downloadHttp($url, $lastmodified = null, $accept = false, $channel = fa
         $length = isset($headers['content-length']) ? $headers['content-length'] : -1;
 
         $data = '';
-        while ($chunk = @fread($fp, 8192)) {
-            $data .= $chunk;
+        if (isset($headers['transfer-encoding']) && strtolower($headers['transfer-encoding']) === 'chunked') {
+            while (!feof($fp)) {
+                $chunk_size = hexdec(fgets($fp));
+                if ($chunk_size === 0) {
+                    break;
+                }
+                $data .= fread($fp, $chunk_size);
+                fgets($fp); // Skip the trailing CRLF
+            }
+        } else {
+            while ($chunk = @fread($fp, 8192)) {
+                $data .= $chunk;
+            }
         }
         fclose($fp);