Turn returned HTTP headers lowercase before parsing

NGINX for some reason returns "content-length" instead of
"Content-Length".

src/Mp3FileLocal.php

@@ -0,0 +1,83 @@
+<?php
+
+namespace wapmorgan\Mp3Info;
+
+class Mp3FileLocal
+{
+    public string $fileName;
+
+    protected int $fileSize;
+
+    private $_filePtr;
+
+    /**
+     * Creates a new local file object.
+     *
+     * @param string $fileName URL to open
+     */
+    public function __construct(string $fileName)
+    {
+        $this->fileName = $fileName;
+        $this->_filePtr = fopen($this->fileName, 'rb');
+        $this->fileSize = filesize($this->fileName);
+    }
+
+    /**
+     * Returns the file size
+     *
+     * @return int File size
+     */
+    public function getFileSize(): int
+    {
+        return $this->fileSize;
+    }
+
+    /**
+     * Returns the given amount of Bytes from the current file position.
+     *
+     * @param int $numBytes Bytes to read
+     *
+     * @return string Read Bytes
+     */
+    public function getBytes(int $numBytes): string
+    {
+        return fread($this->_filePtr, $numBytes);
+    }
+
+    /**
+     * Returns the current file position
+     *
+     * @return int File position
+     */
+    public function getFilePos(): int
+    {
+        return ftell($this->_filePtr);
+    }
+
+    /**
+     * Sets the file point to the given position.
+     *
+     * @param int $posBytes Position to jump to
+     *
+     * @return bool TRUE if successful
+     */
+    public function seekTo(int $posBytes): bool
+    {
+        $result = fseek($this->_filePtr, $posBytes);
+        return ($result == 0);
+    }
+
+    /**
+     * Advances the file pointer the given amount.
+     *
+     * @param int $posBytes Bytes to advance
+     *
+     * @return bool TRUE if successful
+     */
+    public function seekForward(int $posBytes): bool
+    {
+        $newPos = $this->getFilePos() + $posBytes;
+        return $this->seekTo($newPos);
+    }
+
+}

src/Mp3FileRemote.php

@@ -0,0 +1,190 @@
+<?php
+
+namespace wapmorgan\Mp3Info;
+
+use \Exception;
+
+class Mp3FileRemote
+{
+    public string $fileName;
+    public int $blockSize;
+
+    protected $buffer;
+    protected int $filePos;
+    protected $fileSize;
+
+    /**
+     * Creates a new remote file object.
+     *
+     * @param string $fileName  URL to open
+     * @param int    $blockSize Size of the blocks to query from the server (default: 4096)
+     */
+    public function __construct(string $fileName, int $blockSize = 4096)
+    {
+        $this->fileName = $fileName;
+        $this->blockSize = $blockSize;
+        $this->buffer = [];
+        $this->filePos = 0;
+        $this->fileSize = $this->_readFileSize();
+    }
+
+    /**
+     * Returns the file size
+     *
+     * @return int File size
+     */
+    public function getFileSize(): int
+    {
+        return $this->fileSize;
+    }
+
+    /**
+     * Makes a HEAD request to get the file size
+     *
+     * @return int Content-Length header
+     */
+    private function _readFileSize(): int
+    {
+        // make HTTP HEAD request to get Content-Length
+        $context = stream_context_create([
+            'http' => [
+                'method' => 'HEAD',
+            ],
+        ]);
+        $result = get_headers($this->fileName, true, $context);
+        $result = array_change_key_case($result, CASE_LOWER);
+        return $result['content-length'];
+    }
+
+    /**
+     * Returns the given amount of Bytes from the current file position.
+     *
+     * @param int $numBytes Bytes to read
+     *
+     * @return string Read Bytes
+     */
+    public function getBytes(int $numBytes): string
+    {
+        $blockId = intdiv($this->filePos, $this->blockSize);
+        $blockPos = $this->filePos % $this->blockSize;
+        
+        $output = [];
+        
+        do {
+            // make sure we have this block
+            if (!$this->downloadBlock($blockId)) {
+                throw new Exception('Error downloading block ' . $blockId . ' (starting at pos. ' . ($blockId * $this->blockSize) . ')!');
+            }   
+            if ($blockPos + $numBytes >= $this->blockSize) {
+                // length of request is more than this block has, truncate to block len
+                $subLen = $this->blockSize - $blockPos;
+            } else {
+                // requested length fits inside this block
+                $subLen = $numBytes;
+            }
+            // $subLen = ($blockPos + $numBytes >= $this->blockSize) ? ($this->blockSize - $blockPos) : $numBytes;
+            $output[] = substr($this->buffer[$blockId], $blockPos, $subLen);
+            $this->filePos += $subLen;
+            $numBytes -= $subLen;
+            // advance to next block
+            $blockPos = 0;
+            $blockId++;
+        } while ($numBytes > 0);
+        
+        return implode('', $output);
+    }
+
+    /**
+     * Returns the current file position
+     *
+     * @return int File position
+     */
+    public function getFilePos(): int
+    {
+        return $this->filePos;
+    }
+
+    /**
+     * Sets the file pointer to the given position.
+     *
+     * @param int $posBytes Position to jump to
+     *
+     * @return bool TRUE if successful
+     */
+    public function seekTo(int $posBytes): bool
+    {
+        if ($posBytes < 0 || $posBytes > $this->fileSize) {
+            return false;
+        }
+        $this->filePos = $posBytes;
+        return true;
+    }
+
+    /**
+     * Advances the file pointer the given amount.
+     *
+     * @param int $posBytes Bytes to advance
+     *
+     * @return bool TRUE if successful
+     */
+    public function seekForward(int $posBytes): bool
+    {
+        $newPos = $this->filePos + $posBytes;
+        return $this->seekTo($newPos);
+    }
+
+    /**
+     * Downloads the given block if needed
+     *
+     * @param int $blockNo Block to download
+     *
+     * @return bool TRUE if successful
+     */
+    protected function downloadBlock(int $blockNo): bool
+    {
+        if (array_key_exists($blockNo, $this->buffer)) {
+            // already downloaded
+            return true;
+        }
+        $bytesFrom = $blockNo * $this->blockSize;
+        $bytesTo   = $bytesFrom + $this->blockSize - 1;
+        // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Range
+        $context = stream_context_create([
+            'http' => [
+                'method' => 'GET',
+                'header' => [
+                    'Range: bytes=' . $bytesFrom . '-' . $bytesTo,
+                ],
+            ],
+        ]);
+        $filePtr = fopen($this->fileName, 'rb', false, $context);
+        if ($filePtr === false) {
+            return false;
+        }
+        $this->buffer[$blockNo] = fread($filePtr, $this->blockSize);
+        $status = stream_get_meta_data($filePtr);
+        $httpStatus = explode(' ', $status['wrapper_data'][0])[1];
+        if ($httpStatus != '206') {
+            if ($httpStatus != '200') {
+                echo 'Download error!' . PHP_EOL;
+                var_dump($status);
+                return false;
+            }
+            echo 'Server doesn\'t support partial content!' . PHP_EOL;
+            // Content received is whole file from start
+            if ($blockNo != 0) {
+                // move block to start if needed
+                $this->buffer[0] =& $this->buffer[$blockNo];
+                unset($this->buffer[$blockNo]);
+                $blockNo = 0;
+            }
+            // receive remaining parts while we're at it
+            while (!feof($filePtr)) {
+                $blockNo++;
+                $this->buffer[$blockNo] = fread($filePtr, $this->blockSize);
+            }
+        }
+        fclose($filePtr);
+        return true;
+    }
+}