Class FreeImageHostClient

java.lang.Object

com.serinity.accesscontrol.service.FreeImageHostClient

public class FreeImageHostClient
extends Object

Utility client responsible for uploading image files to FreeImage.host using its HTTP API.

This class provides a centralized and static mechanism for sending multipart/form-data HTTP POST requests to the FreeImage.host image upload endpoint. The API key and request URL are loaded from environment variables via EnvironmentVariableLoader.

The client uses Java's HttpClient to construct and execute HTTP requests. Images are uploaded as raw byte arrays within a manually constructed multipart request body.

Configuration:

• IMAGE_API_KEY – Retrieved from environment variables.
• IMAGE_REQUEST_URL – Retrieved from environment variables.

Exposed functionality:

• uploadImage(File) – Uploads an image file and returns its public URL.
• extractImageUrl(String) – Extracts the uploaded image URL from the JSON response.

The upload process:

1. Validates that the provided file exists.
2. Reads the file into memory as a byte array.
3. Constructs a multipart/form-data request body with a unique boundary.
4. Sends the request to the FreeImage.host API using HttpClient.
5. Parses the JSON response to extract the public image URL.

The JSON parsing is performed manually using string operations and brace matching to locate the "image" object and extract its "url" field. Escape sequences (e.g., \/) are cleaned before returning the final URL.

Example usage:

File image = new File("profile.png");
String imageUrl = FreeImageHostClient.uploadImage(image);
System.out.println("Uploaded image URL: " + imageUrl);

Exceptions:

• IllegalArgumentException – If the file does not exist.
• IOException – If an I/O error occurs during file reading or HTTP communication.
• InterruptedException – If the HTTP request is interrupted.
• IllegalStateException – If the response JSON is malformed or does not contain the expected fields.

Note:

• The entire file is loaded into memory before upload; large files may impact memory usage.
• Environment variables must be properly configured; otherwise, the upload request will fail.
• For production-grade systems, consider using a JSON parser library instead of manual string parsing.

Since:

2026-02-16

Version:

1.0

Author:

@ZouariOmar (zouariomar20@gmail.com)

See Also:

• API version 1 FreeImageHostClient.java

Constructor Summary

Constructors

Constructor	Description
FreeImageHostClient()	Creates a new FreeImage.host client holder.

Method Summary

Modifier and Type	Method	Description
static String	extractImageUrl(String jsonResponse)	Extracts "url" field from FreeImage.host JSON response using regex.
static String	uploadImage(File imageFile)	Uploads an image file to FreeImage.host and returns the public URL.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

FreeImageHostClient

public FreeImageHostClient()

Creates a new FreeImage.host client holder.

Method Details

uploadImage

public static String uploadImage(File imageFile)
                          throws IOException,
InterruptedException

Uploads an image file to FreeImage.host and returns the public URL.

Parameters:

imageFile - image file to upload

Returns:

publicly accessible image URL

Throws:

IOException - if reading the file or HTTP transport fails

InterruptedException - if the upload request is interrupted

extractImageUrl

public static String extractImageUrl(String jsonResponse)

Extracts "url" field from FreeImage.host JSON response using regex.

Parameters:

jsonResponse - raw JSON API response

Returns:

extracted image URL