(Node.js) 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.

Note: This example requires Chilkat v11.4.0 or greater.

Install Chilkat for Node.js and Electron using npm at

Chilkat npm packages for Node.js
Chilkat npm packages for Electron
on Windows, Linux, MacOS

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

    var success = false;

    success = false;

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

    var ai = new chilkat.Ai();

    // 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.Provider = "openai";

    // Use your provider's API key.
    ai.ApiKey = "MY_API_KEY";

    // Choose a model.
    ai.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.
    var 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) {
        console.log(ai.LastErrorText);
        return;
    }

    // Get the text response.
    var sbResponse = new chilkat.StringBuilder();
    ai.GetOutputTextSb(sbResponse);
    console.log(sbResponse.GetAsString());

}

chilkatExample();