@dash0/sdk-web/dist/modules/transport/fetch.js

Dash0's Web SDK to collect telemetry from end-users' web browsers

import { vars } from "../vars";
import { noop, warn, fetch, debug } from "../utils";
const BEACON_BODY_SIZE_LIMIT = 60000;
export async function send(path, body) {
    debug("Transmitting telemetry to endpoints", body);
    const jsonString = JSON.stringify(body);
    let requestBody = jsonString;
    let byteLength = jsonString.length;
    let isCompressed = false;
    // Try to compress if supported
    if (typeof CompressionStream !== "undefined" && vars.enableTransportCompression) {
        requestBody = await compressWithGzip(jsonString);
        byteLength = requestBody.byteLength;
        isCompressed = true;
    }
    // Send to all endpoints in parallel
    await Promise.all(vars.endpoints.map(async (endpoint) => {
        try {
            const url = new URL(endpoint["url"]);
            url.pathname = url.pathname + (url.pathname.endsWith("/") ? path.substring(1) : path);
            const headers = {
                "Content-Type": "application/json",
                Authorization: `Bearer ${endpoint["authToken"]}`,
            };
            if (endpoint.dataset) {
                headers["Dash0-Dataset"] = endpoint["dataset"];
            }
            // Try to compress if supported
            if (isCompressed) {
                headers["Content-Encoding"] = "gzip";
            }
            if (!fetch) {
                warn("Unable to send telemetry, fetch is not defined");
                return;
            }
            const response = await fetch(url, {
                method: "POST",
                headers,
                body: requestBody,
                // The keepalive flag is related to the window.sendBeacon API. This in turn has size limitations.
                keepalive: byteLength <= BEACON_BODY_SIZE_LIMIT,
            });
            // read the body so the connection can be closed
            response.text().catch(noop);
            if (!response.ok) {
                warn(`Failed to send telemetry to ${url}: ${response.status} ${response.statusText}`);
            }
        }
        catch (error) {
            warn(`Error sending telemetry to ${endpoint.url}${path}:`, error);
        }
    }));
}
async function compressWithGzip(data) {
    const blob = new Blob([data]);
    const stream = blob.stream();
    const compressedStream = stream.pipeThrough(new CompressionStream("gzip"));
    return new Response(compressedStream).arrayBuffer();
}