Got it, let's break down your two problems and solve them with pure Core PHP—no third-party libraries required. First, we'll fix that messy invalid character issue from file_get_contents(), then build text extractors for .doc, .docx, and .pdf files.

Fixing Invalid Characters from file_get_contents() #

The core issue here is that .doc, .docx, and .pdf are binary file formats, not plain text. When you use file_get_contents() directly, you're reading raw binary data—this includes formatting markers, metadata, and non-printable characters that simple preg_replace calls can't fully strip out.

Here's a better workflow:

1. Extract the actual text content first using format-specific logic (see below)
2. Run this cleanup routine to polish the extracted text:

function cleanExtractedText($text) {
    // Remove non-printable ASCII characters
    $text = preg_replace('/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]/', '', $text);
    // Collapse extra whitespace/line breaks into single spaces
    $text = preg_replace('/\s+/', ' ', $text);
    // Trim leading/trailing whitespace
    return trim($text);
}

If you were trying to clean raw binary data directly, that's why you had leftovers—always extract the text first, then clean it.

Pure Core PHP Text Extraction by File Type #

1. .docx Files #

Docx files are actually ZIP archives with XML inside. We can use PHP's built-in ZipArchive class to pull out the main content:

function extractDocxText($filePath) {
    $zip = new ZipArchive;
    if ($zip->open($filePath) === true) {
        // Main text lives in word/document.xml
        if ($zip->locateName('word/document.xml') !== false) {
            $xmlContent = $zip->getFromName('word/document.xml');
            $zip->close();
            
            // Strip XML tags and clean up
            $text = strip_tags($xmlContent);
            return cleanExtractedText($text);
        }
        $zip->close();
    }
    return false;
}

2. .doc Files #

.doc is a proprietary binary format (OLE Compound Document), so full parsing is tricky in pure PHP. This lightweight method pulls out the main text for most basic documents:

function extractDocText($filePath) {
    $fileHandle = fopen($filePath, 'rb');
    $text = '';
    
    if ($fileHandle) {
        // Skip the OLE header (first 512 bytes)
        fseek($fileHandle, 512);
        
        // Read chunks and extract printable text
        while (!feof($fileHandle)) {
            $chunk = fread($fileHandle, 4096);
            preg_match_all('/[\x20-\x7E\xA0-\xFF]+/', $chunk, $matches);
            if (!empty($matches[0])) {
                $text .= implode(' ', $matches[0]);
            }
        }
        fclose($fileHandle);
        return cleanExtractedText($text);
    }
    return false;
}

Note: This won't handle complex formatting (like tables or embedded objects) perfectly, but it gets the core text content.

3. .pdf Files #

PDFs are binary, but we can parse text streams between BT (begin text) and ET (end text) operators:

function extractPdfText($filePath) {
    $content = file_get_contents($filePath);
    $text = '';
    
    // Grab all text streams
    preg_match_all('/BT(.*?)ET/s', $content, $matches);
    
    foreach ($matches[1] as $stream) {
        // Remove PDF formatting commands and operators
        $stream = preg_replace('/\/[a-zA-Z]+[\s\d]+/', '', $stream);
        $stream = preg_replace('/[\[\]\(\)]/', '', $stream);
        $stream = preg_replace('/\s+/', ' ', $stream);
        // Decode escaped characters like \( or \)
        $stream = preg_replace('/\\\(|\)/', '', $stream);
        $text .= $stream . ' ';
    }
    
    return cleanExtractedText($text);
}

Note: This won't work for encrypted PDFs or image-only PDFs (you can't extract text from images with pure PHP), but it handles regular text-based PDFs well.

Putting It All Together #

Create a wrapper function to detect the file type and call the right extractor:

function extractDocumentText($filePath) {
    $extension = strtolower(pathinfo($filePath, PATHINFO_EXTENSION));
    
    switch ($extension) {
        case 'docx':
            return extractDocxText($filePath);
        case 'doc':
            return extractDocText($filePath);
        case 'pdf':
            return extractPdfText($filePath);
        default:
            return 'Unsupported file type';
    }
}

// Example usage
$text = extractDocumentText('path/to/your/document.pdf');
echo $text;

内容的提问来源于stack exchange，提问作者Priyank