Read the REST Response Body in Chunks

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Demonstrates Rest.ReadRespChunkBd, which reads the response body one chunk at a time, appending each chunk to a BinData. A return value of 0 signals the body is complete, while -1 indicates a read failure.

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

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    const rest = try chilkat.Rest.init();
    defer rest.deinit();
    const b_tls = true;
    const b_auto_reconnect = true;
    rest.connect("example.com", 443, b_tls, b_auto_reconnect) catch {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    rest.sendReqNoBody("GET", "/api/largefile") catch {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    const status_code = rest.readResponseHeader();
    if (status_code < 0) {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    }

    // Check for the expected success status code.  If the response is not 200, the body is likely
    // error text formatted as JSON, XML, or HTML rather than the expected content.  In that case read
    // the body as text, report it, and return.
    if (status_code != 200) {
        const sb_error = try chilkat.StringBuilder.init();
        defer sb_error.deinit();
        rest.readRespSb(sb_error) catch {
            std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
            return;
        };

        std.debug.print("Request failed with status code {d}\n", .{status_code});
        std.debug.print("{s}\n", .{try sb_error.getAsString(alloc)});
        return;
    }

    // The status code is 200.  Read the response body in chunks, appending each chunk to the BinData.
    // Each call waits until at least the requested number of bytes is available, unless the response
    // ends first.  A return value of 0 means the final bytes were returned and the body is complete;
    // -1 indicates a read failure.
    const bd_body = try chilkat.BinData.init();
    defer bd_body.deinit();
    var chunk_result: i32 = rest.readRespChunkBd(8192, bd_body);
    while (chunk_result > 0) {
        chunk_result = rest.readRespChunkBd(8192, bd_body);
    }

    if (chunk_result < 0) {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    }

    std.debug.print("Received {d} bytes.\n", .{bd_body.getNumBytes()});
}