[WIP] feat: Send transactions in envelopes

The new Envelope endpoint and format is what we want to use for
transactions going forward.

TODO: include rationale.

Author: rhcarvalho

packages/browser/src/transports/fetch.ts

@@ -22,24 +22,41 @@ export class FetchTransport extends BaseTransport {
       });
     }
 
-    const defaultOptions: RequestInit = {
-      body: JSON.stringify(event),
+    let payload = JSON.stringify(event);
+    let url = this.url;
+    let headers = this.options.headers || {};
+
+    if (event.type === 'transaction') {
+      url = url.replace('/store', '/envelope');
+      headers['content-type'] = 'application/x-sentry-envelope';
+
+      const envelopeHeaders = JSON.stringify({
+        event_id: event.event_id,
+        sent_at: null,
+      });
+      const itemHeaders = JSON.stringify({
+        content_type: 'application/json',
+        type: event.type,
+      });
+      const envelope = `${envelopeHeaders}\n${itemHeaders}\n${payload}\n`;
+      payload = envelope;
+    }
+
+    const options: RequestInit = {
+      body: payload,
       method: 'POST',
       // Despite all stars in the sky saying that Edge supports old draft syntax, aka 'never', 'always', 'origin' and 'default
       // https://caniuse.com/#feat=referrer-policy
       // It doesn't. And it throw exception instead of ignoring this parameter...
       // REF: https://github.com/getsentry/raven-js/issues/1233
       referrerPolicy: (supportsReferrerPolicy() ? 'origin' : '') as ReferrerPolicy,
+      headers: headers,
     };
 
-    if (this.options.headers !== undefined) {
-      defaultOptions.headers = this.options.headers;
-    }
-
     return this._buffer.add(
       new SyncPromise<Response>((resolve, reject) => {
         global
-          .fetch(this.url, defaultOptions)
+          .fetch(url, options)
           .then(response => {
             const status = Status.fromHttpCode(response.status);
 

packages/browser/src/transports/xhr.ts

@@ -20,6 +20,26 @@ export class XHRTransport extends BaseTransport {
       });
     }
 
+    let payload = JSON.stringify(event);
+    let url = this.url;
+    let headers = this.options.headers || {};
+
+    if (event.type === 'transaction') {
+      url = url.replace('/store', '/envelope');
+      headers['content-type'] = 'application/x-sentry-envelope';
+
+      const envelopeHeaders = JSON.stringify({
+        event_id: event.event_id,
+        sent_at: null,
+      });
+      const itemHeaders = JSON.stringify({
+        content_type: 'application/json',
+        type: event.type,
+      });
+      const envelope = `${envelopeHeaders}\n${itemHeaders}\n${payload}\n`;
+      payload = envelope;
+    }
+
     return this._buffer.add(
       new SyncPromise<Response>((resolve, reject) => {
         const request = new XMLHttpRequest();
@@ -45,13 +65,13 @@ export class XHRTransport extends BaseTransport {
           reject(request);
         };
 
-        request.open('POST', this.url);
-        for (const header in this.options.headers) {
-          if (this.options.headers.hasOwnProperty(header)) {
-            request.setRequestHeader(header, this.options.headers[header]);
+        request.open('POST', url);
+        for (const header in headers) {
+          if (headers.hasOwnProperty(header)) {
+            request.setRequestHeader(header, headers[header]);
           }
         }
-        request.send(JSON.stringify(event));
+        request.send(payload);
       }),
     );
   }

packages/node/src/transports/base.ts

@@ -84,7 +84,26 @@ export abstract class BaseTransport implements Transport {
     }
     return this._buffer.add(
       new Promise<Response>((resolve, reject) => {
-        const req = httpModule.request(this._getRequestOptions(), (res: http.IncomingMessage) => {
+        const options = this._getRequestOptions();
+        let payload = JSON.stringify(event);
+
+        if (event.type === 'transaction') {
+          options.path = (options.path || '').replace('/store', '/envelope');
+          (options.headers || {})['content-type'] = 'application/x-sentry-envelope';
+
+          const envelopeHeaders = JSON.stringify({
+            event_id: event.event_id,
+            sent_at: null,
+          });
+          const itemHeaders = JSON.stringify({
+            content_type: 'application/json',
+            type: event.type,
+          });
+          const envelope = `${envelopeHeaders}\n${itemHeaders}\n${payload}\n`;
+          payload = envelope;
+        }
+
+        const req = httpModule.request(options, (res: http.IncomingMessage) => {
           const statusCode = res.statusCode || 500;
           const status = Status.fromHttpCode(statusCode);
 
@@ -118,7 +137,7 @@ export abstract class BaseTransport implements Transport {
           });
         });
         req.on('error', reject);
-        req.end(JSON.stringify(event));
+        req.end(payload);
       }),
     );
   }