That 415 error usually pops up when the server doesn’t recognize the media type you’re sending, and in your case, there are a couple of misalignments between your Axios request and the original cURL command. Let’s break down the fixes step by step:

1. Wrong Authentication Approach #

Your cURL uses -u for Basic Authentication, but your Axios code tries to pass username and password directly in headers—this isn’t how Basic Auth works here. Axios has a built-in auth config option that automatically generates the correct Authorization header for you.

2. Manual Content-Type Header Breakage #

When sending FormData with Axios, don’t manually set the Content-Type header. Axios will automatically set it to multipart/form-data with the required boundary parameter. If you set it manually, you’ll omit this boundary, which the server needs to parse the form data correctly—this is a common cause of 415 errors.

3. Tweak the FormData Content Field #

While JSON.stringify(mapping) is valid, ensure the file options are properly passed to the FormData.append method (some environments need explicit syntax for the options object).

Corrected Axios Code #

const url = `https://serverless-upload.twilio.com/v1/Services/${service_uid}/Assets/${asset_uid}/Versions`;
const form = new FormData();

// Match the cURL form fields exactly
form.append('Path', 'mapping.json');
form.append('Visibility', 'private');
// Append JSON content with correct filename and content type
form.append('Content', JSON.stringify(mapping), {
  filename: 'mapping.json',
  contentType: 'application/json'
});

try {
  const response = await axios.post(url, form, {
    // Use Axios's native auth for Basic Authentication
    auth: {
      username: client.accountSid,
      password: client.password
    }
    // No manual Content-Type header needed—Axios handles this
  });
  console.log('Upload successful:', response.data);
} catch (error) {
  console.error('Upload failed:', error.response?.data || error.message);
}

Extra Checks for Node.js Environments #

If you’re running this in Node.js, install the form-data package (npm install form-data) and import it, since Node’s native FormData behaves differently from browser implementations:

const FormData = require('form-data');

Also double-check that mapping is a valid JSON object before stringifying it—invalid JSON can cause hidden parsing issues on the server side.

This adjustment aligns your Axios request perfectly with the original cURL command, fixing the 415 error by sending the correct media type and authentication headers.

内容的提问来源于stack exchange，提问作者darkrai