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One of the most common reasons is an incorrect file path. When calling hash_hmac_file(), the file path must be accurate. PHP resolves file paths based on the current working directory, so if the provided path is wrong or the relative path is incorrect relative to the current script, it will cause a “File not found” error.
Confirm whether the absolute path of the file is correct. If using a relative path, make sure it is correct relative to the directory where the PHP script is currently located.
Use the realpath() function to get the file’s absolute path to ensure the path is resolved correctly.
<span><span><span class="hljs-variable">$file_path</span></span><span> = </span><span><span class="hljs-string">'path/to/your/file.txt'</span></span><span>;
</span><span><span class="hljs-variable">$absolute_path</span></span><span> = </span><span><span class="hljs-title function_ invoke__">realpath</span></span><span>(</span><span><span class="hljs-variable">$file_path</span></span><span>);
</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$absolute_path</span></span> === </span><span><span class="hljs-literal">false</span></span><span>) {
</span><span><span class="hljs-keyword">echo</span></span> <span>"File not found"</span>;
} </span><span>else</span> {
</span><span><span class="hljs-keyword">echo</span></span> <span>"The absolute path of the file is: " . </span><span>$absolute_path</span>;
}
</span></span>Even if the file path is correct, the PHP process needs sufficient permissions to access the file. If the file permissions are set incorrectly, PHP may not be able to read the file contents, causing a “File not found” error.
Check if the file is readable by the PHP user.
Use the chmod command to change the file permissions so the PHP user can read the file.
<span><span><span class="hljs-built_in">chmod</span></span> 644 path/to/your/file.txt
</span></span>If PHP runs under the web server user, ensure that user has read permissions on the file. Typically, the web server user is www-data or apache. You can check the current file permissions with the following command:
<span><span><span class="hljs-built_in">ls</span></span> -l path/to/your/file.txt
</span></span>The PHP configuration file php.ini may impose restrictions on file access paths. For example, the open_basedir directive limits the paths PHP can access. If open_basedir is set, PHP cannot access files outside of the specified paths.
Check if the open_basedir setting exists in the php.ini file.
If there are restrictions, modify the php.ini file to add the required directories or disable the open_basedir restriction.
<span><span><span class="hljs-attr">open_basedir</span></span> = /var/www:/tmp:/usr/share/php:/path/to/your/files
</span></span>After making changes, remember to restart the web server or PHP-FPM service.
Before executing hash_hmac_file(), first confirm that the file actually exists. If the file does not exist, PHP will return a “File not found” error.
Use the file_exists() function to check if the file exists before calling hash_hmac_file().
<span><span><span class="hljs-variable">$file_path</span></span><span> = </span><span><span class="hljs-string">'path/to/your/file.txt'</span></span><span>;
</span><span><span class="hljs-keyword">if</span></span><span> (!</span><span><span class="hljs-title function_ invoke__">file_exists</span></span><span>(</span><span><span class="hljs-variable">$file_path</span></span><span>)) {
</span><span><span class="hljs-keyword">echo</span></span> <span>"File does not exist"</span>;
} </span><span>else</span> {
</span><span><span class="hljs-keyword">echo</span></span> <span>"File exists, proceeding"</span>;
}
</span></span>If the file does not exist, verify whether the file path is correct or if the file has been deleted, moved, or renamed.
If the file name contains special or non-ASCII characters, PHP may fail to recognize the file path correctly in some environments, resulting in a file-not-found error.
Ensure there are no illegal characters in the file path. If special or non-ASCII characters are present, try converting the file path encoding using functions like mb_convert_encoding() or utf8_encode().
<span><span><span class="hljs-variable">$file_path</span></span><span> = </span><span><span class="hljs-string">'path/with/special_chars.txt'</span></span><span>;
</span><span><span class="hljs-variable">$encoded_path</span></span><span> = </span><span><span class="hljs-title function_ invoke__">mb_convert_encoding</span></span><span>(</span><span><span class="hljs-variable">$file_path</span></span>, </span><span><span class="hljs-string">'UTF-8'</span></span>, </span><span><span class="hljs-string">'GB2312'</span></span><span>);
</span></span>If you are sure the file is in a fixed location, the safest approach is to use an absolute path instead of a relative one. This avoids errors caused by PHP’s current working directory being different.
Use the __DIR__ constant to get the current file’s absolute path, and combine it with the relative path to ensure accuracy.
<span><span><span class="hljs-variable">$file_path</span></span><span> = </span><span><span class="hljs-keyword">__DIR__</span></span> . </span><span><span class="hljs-string">'/path/to/your/file.txt'</span></span>;
</span></span>