mockserver-client

An idiomatic Rust client for MockServer's control-plane REST API.

Installation

Add to your Cargo.toml:

[dev-dependencies]
mockserver-client = "7.0"

Quick Start

use mockserver_client::{ClientBuilder, HttpRequest, HttpResponse, VerificationTimes};

fn main() -> mockserver_client::Result<()> {
    let client = ClientBuilder::new("localhost", 1080).build()?;

    // Create an expectation
    client.when(HttpRequest::new().method("GET").path("/hello"))
        .respond(HttpResponse::new().status_code(200).body("world"))?;

    // Verify the request was received
    client.verify(
        HttpRequest::new().path("/hello"),
        VerificationTimes::at_least(1),
    )?;

    // Reset all expectations
    client.reset()?;
    Ok(())
}

Features

• Fluent builder API — client.when(request).respond(response)
• Response, Forward, and Error actions — full MVP control-plane coverage
• Verification — verify (count-based) and verify_sequence (order-based)
• Retrieve — recorded requests, active expectations, recorded expectations, logs
• Clear / Reset — by request matcher, by expectation ID, or full reset
• Status / Bind — query ports, bind additional ports
• Blocking (synchronous) — uses reqwest blocking client; no async runtime needed
• TLS support — optional HTTPS with configurable certificate verification

API Overview

use mockserver_client::*;

let client = ClientBuilder::new("localhost", 1080).build().unwrap();

// Fluent expectation creation
client.when(HttpRequest::new().method("POST").path("/api/users"))
    .times(Times::exactly(3))
    .respond(HttpResponse::new()
        .status_code(201)
        .header("Location", "/api/users/1")
        .body(r#"{"id": 1}"#))?;

// Forward action
client.when(HttpRequest::new().path("/proxy"))
    .forward(HttpForward::new("backend.local", 8080).scheme("HTTP"))?;

// Verify
client.verify(
    HttpRequest::new().method("POST").path("/api/users"),
    VerificationTimes::between(1, 3),
)?;

// Verify sequence
client.verify_sequence(vec![
    HttpRequest::new().path("/first"),
    HttpRequest::new().path("/second"),
])?;

// Clear by request matcher
client.clear(
    Some(&HttpRequest::new().path("/api/users")),
    Some(ClearType::Expectations),
)?;

// Clear by ID
client.clear_by_id("my-expectation-id", None)?;

// Retrieve recorded requests
let requests = client.retrieve_recorded_requests(None)?;

// Retrieve active expectations
let expectations = client.retrieve_active_expectations(None)?;

// Server status
let ports = client.status()?;
println!("Listening on: {:?}", ports.ports);

// Reset everything
client.reset()?;

Interactive Breakpoints

Register breakpoint matchers to pause forwarded/proxied traffic at REQUEST, RESPONSE, RESPONSE_STREAM, or INBOUND_STREAM phases. A callback WebSocket connection is opened automatically.

use mockserver_client::*;

let client = ClientBuilder::new("localhost", 1080).build()?;

// REQUEST-only breakpoint
let id = client.add_request_breakpoint(
    HttpRequest::new().path("/api/.*"),
    Box::new(|req| Some(req)),  // continue with original
)?;

// REQUEST + RESPONSE breakpoint
let id2 = client.add_request_response_breakpoint(
    HttpRequest::new().path("/api/.*"),
    Box::new(|req| Some(req)),
    Box::new(|_req, resp| Some(resp)),
)?;

// Streaming breakpoint
let id3 = client.add_stream_breakpoint(
    HttpRequest::new().path("/stream/.*"),
    &[phase::RESPONSE_STREAM],
    Box::new(|frame| {
        Some(StreamFrameDecision::continue_frame(&frame.correlation_id))
    }),
)?;

// Manage matchers
let list = client.list_breakpoint_matchers()?;
client.remove_breakpoint_matcher(&id)?;
client.clear_breakpoint_matchers()?;
client.close_breakpoint_websocket();

Stream frame decisions: StreamFrameDecision::continue_frame, ::modify, ::drop_frame, ::inject, ::close.

Start / Launch MockServer

The Rust client can download and launch a local MockServer instance directly -- no Java installation and no Docker required. The launcher downloads a self-contained platform bundle (mockserver-<version>-<os>-<arch>) from the GitHub Release, verifies its SHA-256, caches it per-user, and starts it.

Quick start

use mockserver_client::launcher;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut handle = launcher::start(1080)?;
    println!("MockServer running on port {}", handle.port());

    // ... use MockServer ...

    handle.stop()?;
    Ok(())
}

Just ensure the binary is present

let launcher_path = launcher::ensure_launcher()?;
println!("Launcher at: {}", launcher_path.display());

Specify a version

let mut handle = launcher::start_with_version(
    "7.1.0", 1080, &launcher::EnsureOptions::default()
)?;

API reference

Supported platforms

Environment variables

Version

By default the launcher downloads the MockServer version matching this crate (derived from Cargo.toml at compile time via env!("CARGO_PKG_VERSION")). Pass an explicit version to override.

Building

cargo build
cargo test
cargo clippy

Integration Tests

Integration tests require a running MockServer and are skipped by default:

# Start MockServer (e.g., via Docker)
docker run -d -p 1080:1080 mockserver/mockserver

# Run integration tests
MOCKSERVER_URL=http://localhost:1080 cargo test -- --ignored

License

Apache-2.0