Solving the FormData Issue in Axios Requests Using Vue.js

---

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---

The Problem Statement

The issue arose when attempting to send a combination of files and text fields in a single request. While integers sent just fine, strings were mysteriously failing to be transmitted.

Here’s a simplified version of the code that shows how the user attempted to send data with Axios using FormData:

[[See Video to Reveal this Text or Code Snippet]]

Despite this seemingly straightforward approach, strings were not reaching the server when sent. This left the developer puzzled and seeking clarity on what caused this inconsistency.

Understanding the Issue

The server-side PHP code was set up to handle incoming data but could not correctly process string values. Here’s the pivotal snippet that facilitated the issue:

[[See Video to Reveal this Text or Code Snippet]]

Key Insights:

Multipart Form Data: The request body used for FormData is serialized as multipart/form-data, not JSON. Thus, trying to decode it as JSON (like json_decode()) would lead to issues.

Direct Access via PHP: Using $_POST and $_FILES is the appropriate approach here, as they directly handle multipart form data without conversion issues.

The Solution

To properly handle data sent via FormData in your PHP script, adjustments should be made both in the handling script and the Axios request setup.

PHP Server-Side Changes

Instead of using file_get_contents("php://input"), switch to accessing data as follows:

[[See Video to Reveal this Text or Code Snippet]]

Important Points to Remember

Avoid JSON Decoding:

For multipart data, do not use json_decode() on the expected string fields.

Access the data directly through $_POST and $_FILES.

Content-Type Handling:

Do not manually set the Content-Type header in Axios to multipart/form-data. The browser automatically includes the correct boundary parameter when a FormData object is sent.

Remove the line setting the header:

[[See Video to Reveal this Text or Code Snippet]]

Example of Final Axios Code

Your final Axios request should look like this:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion