Zig 0.15.1 http-client GET example

http-fetch.zig

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

// This version won't read/print headers, just the response
pub fn main() !void {
    var writer_buffer: [8 * 1024]u8 = undefined;
    var redirect_buffer: [8 * 1024]u8 = undefined;

    var writer = std.fs.File.stdout().writer(&writer_buffer);

    var debug_allocator: std.heap.DebugAllocator(.{}) = .init;

    defer switch (builtin.mode) {
        .Debug => std.debug.assert(debug_allocator.deinit() == .ok),
        .ReleaseFast, .ReleaseSmall, .ReleaseSafe => {
            // Nothing
        },
    };

    const allocator = switch (builtin.mode) {
        .Debug => debug_allocator.allocator(),
        .ReleaseFast, .ReleaseSmall, .ReleaseSafe => std.heap.smp_allocator,
    };

    const uri = try std.Uri.parse("https://postman-echo.com/get");

    var client: std.http.Client = .{ .allocator = allocator };

    defer client.deinit();

    const result = try client.fetch(.{
        .location = .{ .uri = uri },
        .method = .GET,
        .redirect_buffer = &redirect_buffer,
        .response_writer = &writer.interface,
    });

    if (builtin.mode == .Debug) {
        std.debug.assert(result.status == .ok);
    }

    try writer.interface.flush();
}

http-get.zig

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

// Manual http request printing also the response headers (won't work if chunked or compressed)
pub fn main() !void {
    var writer_buffer: [8 * 1024]u8 = undefined;
    var redirect_buffer: [8 * 1024]u8 = undefined;
    var transfer_buffer: [8 * 1024]u8 = undefined;
    var reader_buffer: [8 * 1024]u8 = undefined;

    var writer = std.fs.File.stdout().writer(&writer_buffer);

    var debug_allocator: std.heap.DebugAllocator(.{}) = .init;

    defer switch (builtin.mode) {
        .Debug => std.debug.assert(debug_allocator.deinit() == .ok),
        .ReleaseFast, .ReleaseSmall, .ReleaseSafe => {
            // Nothing
        },
    };

    const allocator = switch (builtin.mode) {
        .Debug => debug_allocator.allocator(),
        .ReleaseFast, .ReleaseSmall, .ReleaseSafe => std.heap.smp_allocator,
    };

    const uri = try std.Uri.parse("https://postman-echo.com/get");

    var client: std.http.Client = .{ .allocator = allocator };

    defer client.deinit();

    var request = try client.request(.GET, uri, .{});

    defer request.deinit();

    try request.sendBodiless();

    const response = try request.receiveHead(&redirect_buffer);

    _ = try writer.interface.write(response.head.bytes);

    const content_length = response.head.content_length;
    const reader = request.reader.bodyReader(&transfer_buffer, .none, content_length);

    var done = false;
    var bytes_read: usize = 0;

    while (!done) {
        const size = try reader.readSliceShort(&reader_buffer);

        if (size > 0) {
            bytes_read += size;
            _ = try writer.interface.write(reader_buffer[0..size]);
        }

        if (content_length) |c_len| {
            if (bytes_read >= c_len) {
                done = true;
            }
        }

        if (size < reader_buffer.len) {
            done = true;
        }
    }

    try writer.interface.flush();
}

The variable names made me think you were accidentally using the reader's internal fifo buffer as your temporary bounce buffer, but no you gave the reader transfer_buffer instead of reader_buffer.

Maybe this change would make more sense?

-   const reader = request.reader.bodyReader(&transfer_buffer, .none, content_length);
+   const reader = request.reader.bodyReader(&reader_buffer, .none, content_length);

    var done = false;
    var bytes_read: usize = 0;

    while (!done) {
-       const size = try reader.readSliceShort(&reader_buffer);
+       const size = try reader.readSliceShort(&transfer_buffer);

        if (size > 0) {
            bytes_read += size;
-           _ = try writer.interface.write(reader_buffer[0..size]);
+           _ = try writer.interface.write(transfer_buffer[0..size]);

// ...

-       if (size < reader_buffer.len) {
+       if (size < transfer_buffer.len) {
            done = true;
        }

Yeah the names are confusing indeed, I used transfer since it's in the "middle", used for piping the data in the buffer I finally use for reading the response. But it would make more sense to change the names, yes. It doesn't change the example code much anyway