Extending Moco API to Support Delayed Responses for Mocking Slow Endpoints

When using the Moco API for interface simulation, the author needed to mock an endpoint whose response time exceeds 5 seconds in order to observe how the client handles such latency.

Although Moco already provides a delay feature, it only works for asynchronous requests and cannot produce a delayed response for a normal request, so the author created an extension to add this capability.

Demo Usage

HttpServer server = getServer(8088)

        server.get(urlOnly("/aba")).response(delay(textRes("faun"), 5000))

        server.response("haha")

        MocoServer drive = run(server)

        waitForKey("fan")

        drive.stop()

Wrapper Methods

/**
 * Delayed response
 * @param handler
 * @param time time in ms, cannot be lower than 50ms due to a known bug
 */
static ResponseHandler delay(ResponseHandler handler, int time) {
        DelayHandler.newSeq(handler, time)
}

/**
 * Delayed response with default 1000ms
 * @param handler
 */
static ResponseHandler delay(ResponseHandler handler) {
        DelayHandler.newSeq(handler, 1000)
}

ResponseHandler Implementation (DelayHandler)

package com.fun.moco.support

import com.github.dreamhead.moco.ResponseHandler
import com.github.dreamhead.moco.handler.AbstractResponseHandler
import com.github.dreamhead.moco.internal.SessionContext
import java.util.concurrent.TimeUnit
import static com.google.common.base.Preconditions.checkArgument

/**
 * Extension of ResponseHandler to add delayed response capability
 */
class DelayHandler extends AbstractResponseHandler {

    /** delay time */
    private final int time

    private final ResponseHandler handler

    private DelayHandler(ResponseHandler handler, int time) {
        this.time = time
        this.handler = handler
    }

    public static ResponseHandler newSeq(final ResponseHandler handler, int time) {
        checkArgument(handler != null, "responsehandler cannot be null!")
        return new DelayHandler(handler, time)
    }

    @Override
    void writeToResponse(SessionContext context) {
        com.github.dreamhead.moco.util.Idles.idle(time, TimeUnit.MILLISECONDS)
        handler.writeToResponse(context)
    }
}

Disclaimer : This is the original “FunTester” article; redistribution is prohibited without permission. For collaborations, contact [email protected] .