How to POST a File String Using cURL in PHP Without Temporary Files?

POSTing a File String Using cURL in PHP

The task of sending a file along with other form data becomes more intricate when the file is represented solely as a string. This tutorial demonstrates how to use cURL in PHP to construct the request and bypass temporary file creation.

Solution

Analyzing a sample POST request from a browser reveals a multipart/form-data structure with a unique boundary. Replicating this format manually involves:

1. Creating a Form Data Body: Separate the file and non-file fields and concatenate them with appropriate headers and delimiters. Example:

--boundary
Content-Disposition: form-data; name="otherfield"
Content-Type: text/plain

other field content
--boundary
Content-Disposition: form-data; name="filename"; filename="test.jpg"
Content-Type: image/jpeg

raw JPEG data
--boundary--

2. Setting cURL Options: Configure cURL to handle the POST request with multipart/form-data and specify the content length.

<code class="php">$options = array(
    // Send post data over a POST request
    CURLOPT_POST => true,
    CURLOPT_HTTPHEADER => array(
        // Content-type to multipart/form-data with boundary
        'Content-Type: multipart/form-data; boundary='.$delimiter,
        // Content-Length to the length of our multipart form data
        'Content-Length: ' . strlen($data)
    )
);</code>

3. Execute cURL Request: Use curl_setopt to set the POST fields and execute the request.

<code class="php">curl_setopt($handle, CURLOPT_POSTFIELDS, $data);
curl_exec($handle);</code>

By crafting the body and setting appropriate headers, we simulate a POST request from a browser and avoid creating temporary files.

The above is the detailed content of How to POST a File String Using cURL in PHP Without Temporary Files?. For more information, please follow other related articles on the PHP Chinese website!