Multipart Form Data Example

Demonstrates how to use the built-in multipart/form-data encoding and parsing support (RFC 2046) in httpx.zig.

Features Covered

• Multipart Body Builder: Appending normal text fields and uploading files with custom file names and mime-types.
• Boundary Extraction: Reading boundaries cleanly from incoming Content-Type headers (handles quoted boundaries and boundary extraction edge cases).
• Multipart Payload Parser: Decoding raw multipart payloads back into distinct structured parts.
• Request Integration: Building and attaching multipart payloads to client HTTP requests.

Code Example

const std = @import("std");
const httpx = @import("httpx");

pub fn main() !void {
    var gpa: std.heap.DebugAllocator(.{}) = .init;
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();

    const boundary = "----httpxBoundary7MA4YWxkTrZu0gW";
    var builder = httpx.MultipartBuilder.init(allocator, boundary);
    defer builder.deinit();

    // Add fields and files
    try builder.addField("username", "alice");
    try builder.addFile("avatar", "avatar.png", "image/png", &.{ 0x89, 0x50, 0x4E, 0x47 });

    const body = try builder.build();
    defer allocator.free(body);

    const ct = try builder.contentType();
    defer allocator.free(ct);

    // Parse the generated body back
    var parsed = try httpx.multipart.parse(allocator, body, boundary);
    defer parsed.deinit();

    for (parsed.parts) |part| {
        std.debug.print("Part: {s}, Content-Type: {s}, Data Size: {d}\n", .{
            part.name, part.content_type, part.data.len,
        });
    }
}

Running the Example

Run the pre-configured multipart example:

zig build run-multipart_example