gRPC Scripting

Bruno lets you write JavaScript that runs at specific points in a gRPC call’s lifecycle. Use scripts to set metadata before the call starts, inspect messages as they are sent and received, and run tests against the final status and trailers.

gRPC scripting is a Beta feature. Enable it under Preferences → Beta → gRPC Scripting before the Script tab appears on gRPC requests. See Preferences.

Lifecycle hooks

Open a gRPC request and select the Script tab. The tab contains one editor per hook:

Hook	Runs	Available objects
Before Call Start	Once, before the call is sent	`bru.grpc.request`
Before Message Send	Before each message is transmitted	`bru.grpc.request` (with `message`)
After Message Receive	After each message arrives from the server	`bru.grpc.request`, `bru.grpc.response` (with `message`)
After Call End	Once, after the call completes	`bru.grpc.request`, `bru.grpc.response`

For a unary call, each hook runs once. For streaming calls, the message hooks run once per message sent or received.

The `bru.grpc` API

gRPC scripts use the same bru object as HTTP scripts for variables, assertions, and utilities. Instead of the req and res globals, the request and response models live under bru.grpc.

Everything under bru.grpc is read-only, with one exception: bru.grpc.request.metadata accepts writes in the Before Call Start hook. Calling a write method on metadata in any other hook throws an error. bru.runRequest() is not supported in gRPC scripts.

`bru.grpc.request`

Property	Description
`url`	The request URL.
`method`	The full method path being called.
`methodType`	The call type: unary, server streaming, client streaming, or bidirectional.
`authMode`	The configured auth mode, or `none`.
`protoPath`	Path to the proto file, when one is used.
`name`	The request name.
`metadata`	The metadata sent with the call. Writable only in Before Call Start.
`messages`	Messages the call has sent so far, as `{ data, timestamp }` entries. Empty in Before Call Start.
`message`	The single message about to be sent. Present only in Before Message Send.

`bru.grpc.response`

Available in the After Message Receive and After Call End hooks.

Property	Description
`statusCode`	The gRPC status code.
`statusText`	The gRPC status text.
`metadata`	Response metadata (headers). Read-only.
`trailers`	Response trailers. Read-only.
`messages`	Messages received so far, as `{ data, timestamp }` entries.
`duration`	Call duration.
`message`	The single message just received. Present only in After Message Receive.

In After Message Receive the call is still open, so statusCode, statusText, duration, and trailers are not yet known and read as undefined or empty. They are complete in After Call End.

Metadata methods

metadata on the request and metadata and trailers on the response share the same list API. Keys are matched case-insensitively.

Method	Description
`get(key)`	Get the value of an entry.
`one(key)`	Get the full `{ key, value }` entry.
`has(key, value?)`	Check whether an entry exists, optionally matching its value.
`all()`	Get all entries as an array of `{ key, value }`.
`indexOf(item)`	Get the index of an entry by key or `{ key, value }`.
`each(fn)`, `find(fn)`, `filter(fn)`, `map(fn)`, `reduce(fn)`	Iterate over entries.
`toString()`	Render entries as `key: value` lines.
`upsert(key, value)`	Insert a key, or update it in place. Write method.
`add(item)`	Upsert an entry from a `{ key, value }` object. Write method.
`remove(key)`	Remove the entry with the given key. Write method.
`clear()`	Remove every entry. Write method.

Write methods work only on bru.grpc.request.metadata in the Before Call Start hook.

Message methods

messages on the request and response is a read-only list.

Method	Description
`all()`	Get all messages.
`get(index?)`	Get the message at an index. Defaults to `0`.
`count()`	Get the number of messages.
`each(fn)`, `find(fn)`, `filter(fn)`, `map(fn)`, `reduce(fn)`	Iterate over messages.

Each message is a { data, timestamp } object, where data is the decoded message payload.

Examples

Set an auth token in metadata before the call starts:

// Before Call Start
bru.grpc.request.metadata.upsert("authorization", `Bearer ${bru.getEnvVar("token")}`);

Capture a value from a received message:

// After Message Receive
const reply = bru.grpc.response.message;
bru.setVar("lastReply", reply.data);

Test the final call status and trailers:

// After Call End
test("call succeeded", function () {
  expect(bru.grpc.response.statusCode).to.equal(0);
});

test("received all replies", function () {
  expect(bru.grpc.response.messages.count()).to.be.above(0);
});

Test results and script errors appear in the response pane, grouped by the hook they came from.

API Client

Send Requests

Variables

Authentication

Secret Management

Tests

Scripts

Git & Collaboration

AI

Apps

Settings

Debugging

Lifecycle hooks

The `bru.grpc` API

`bru.grpc.request`

`bru.grpc.response`

Metadata methods

Message methods

Examples

​Lifecycle hooks

​The bru.grpc API

​bru.grpc.request

​bru.grpc.response

​Metadata methods

​Message methods

​Examples

Lifecycle hooks

The `bru.grpc` API

`bru.grpc.request`

`bru.grpc.response`

Metadata methods

Message methods

Examples