PHP Extension

Referencing a Pre-Uploaded File by file_id in an AI Request

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Some AI proviers have a Files API that lets you upload content once and then reference it later in generation requests using a file_id. This is especially useful for large documents, reuse across multiple prompts, or keeping inputs structured and separate from your prompt text.

This example demonstrates how to use a file_id in a request.

PHP Extension

<?php

include("chilkat.php");

$success = false;

$success = false;

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

$ai = new CkAi();

// The provider can be "openai", "google", "claude", "mistral", "deepseek", "xai", or any provider
// that supports referencing pre-uploaded files by a file_id (or file uri).
$ai->put_Provider('openai');

// Use your provider's API key.
$ai->put_ApiKey('MY_API_KEY');

// Choose a model.
$ai->put_Model('gpt-5-mini');

// See the following example showing how to upload a file
// Upload a File to an AI Provider (OpenAI, Google, Antropic, X)

// Use the file_id of the pre-uploaded file.
$file_id = 'file-5G2xncrEiHbVfYPRpFgP9c';
$ai->InputAddFileId($file_id,'application/json');

$ai->InputAddText('Explain why Hamlet delays taking revenge, using only evidence from the file.');

// Ask the AI for text output.
$success = $ai->Ask('text');
if ($success == false) {
    print $ai->lastErrorText() . "\n";
    exit;
}

// Get the text response.
$sbResponse = new CkStringBuilder();
$ai->GetOutputTextSb($sbResponse);
print $sbResponse->getAsString() . "\n";

?>