MemoryTape no longer maintains a read position so it is thread safe. F…

…ixes #57

src/main/groovy/co/freeside/betamax/Tape.groovy

@@ -50,31 +50,23 @@ interface Tape {
 	int size()
 
 	/**
-	 * Attempts to find a recorded interaction on the tape that matches the supplied request's method and URI. If the
-	 * method succeeds then subsequent calls to `play` will play back the response that was found.
+	 * Attempts to find a recorded interaction on the tape that matches the supplied request.
 	 * @param request the HTTP request to match.
 	 * @return `true` if a matching recorded interaction was found, `false` otherwise.
 	 */
 	boolean seek(Request request)
 
-	/**
-	 * Resets the tape so that no recorded interaction is ready to play. Subsequent calls to `play` will throw
-	 * `IllegalStateException` until a successful call to `seek` is made.
-	 */
-	void reset()
-
 	/**
 	 * Plays back a previously recorded interaction to the supplied response. Status, headers and entities are copied
 	 * from the recorded interaction to `response`.
 	 * @param response the HTTP response to populate.
-	 * @throws IllegalStateException if no recorded interaction has been found by a previous call to `seek`.
+	 * @throws IllegalStateException if no matching recorded interaction exists.
 	 */
-	void play(Response response)
+	void play(Request request, Response response)
 
 	/**
-	 * Records a new interaction to the tape. If the tape is currently positioned to read a recorded interaction due to
-	 * a previous successful `seek` call then this method will overwrite the existing recorded interaction. Otherwise
-	 * the newly recorded interaction is appended to the tape.
+	 * Records a new interaction to the tape. If `request` matches an existing interaction this method will overwrite
+	 * it. Otherwise the newly recorded interaction is appended to the tape.
 	 * @param request the request to record.
 	 * @param response the response to record.
 	 * @throws UnsupportedOperationException if this `Tape` implementation is not writable.

src/main/groovy/co/freeside/betamax/proxy/RecordAndPlaybackProxyInterceptor.groovy

@@ -43,7 +43,7 @@ class RecordAndPlaybackProxyInterceptor implements VetoingProxyInterceptor {
 		} else if (tape.seek(request) && tape.isReadable()) {
 			log.info "playing back from tape '$tape.name'..."
 			response.addHeader(X_BETAMAX, "PLAY")
-			tape.play(response)
+			tape.play(request, response)
 			true
 		} else if (!tape.isWritable()) {
 			response.setError(HTTP_FORBIDDEN, "Tape is read-only")

src/main/groovy/co/freeside/betamax/tape/MemoryTape.groovy

@@ -35,7 +35,6 @@ class MemoryTape implements Tape {
 	List<RecordedInteraction> interactions = []
 	private TapeMode mode = READ_WRITE
 	private Comparator<Request>[] matchRules = [method, uri]
-	private int position = -1
 
 	void setMode(TapeMode mode) {
 		this.mode = mode
@@ -57,23 +56,20 @@ class MemoryTape implements Tape {
 		interactions.size()
 	}
 
+
 	boolean seek(Request request) {
 		def requestMatcher = new RequestMatcher(request, matchRules)
-		position = interactions.findIndexOf {
+		interactions.any {
 			requestMatcher.matches(it.request)
 		}
-		position >= 0
 	}
 
-	void reset() {
-		position = -1
-	}
+	void play(Request request, Response response) {
+		if (!mode.readable) throw new IllegalStateException("the tape is not readable")
 
-	void play(Response response) {
-		if (!mode.readable) {
-			throw new IllegalStateException("the tape is not readable")
-		} else if (position < 0) {
-			throw new IllegalStateException("the tape is not ready to play")
+		int position = findMatch(request)
+		if (position < 0) {
+			throw new IllegalStateException("no matching recording found")
 		} else {
 			def interaction = interactions[position]
 			response.status = interaction.response.status
@@ -94,15 +90,14 @@ class MemoryTape implements Tape {
 	}
 
 	void record(Request request, Response response) {
-		if (mode.writable) {
-			def interaction = new RecordedInteraction(request: recordRequest(request), response: recordResponse(response), recorded: new Date())
-			if (position >= 0) {
-				interactions[position] = interaction
-			} else {
-				interactions << interaction
-			}
+		if (!mode.writable) throw new IllegalStateException("the tape is not writable")
+
+		def interaction = new RecordedInteraction(request: recordRequest(request), response: recordResponse(response), recorded: new Date())
+		int position = findMatch(request)
+		if (position >= 0) {
+			interactions[position] = interaction
 		} else {
-			throw new IllegalStateException("the tape is not writable")
+			interactions << interaction
 		}
 	}
 
@@ -111,6 +106,13 @@ class MemoryTape implements Tape {
 		"Tape[$name]"
 	}
 
+	private int findMatch(Request request) {
+		def requestMatcher = new RequestMatcher(request, matchRules)
+		interactions.findIndexOf {
+			requestMatcher.matches(it.request)
+		}
+	}
+
 	private static RecordedRequest recordRequest(Request request) {
 		def clone = new RecordedRequest()
 		clone.method = request.method

src/test/groovy/co/freeside/betamax/proxy/ProxyRecordAndPlaybackSpec.groovy

@@ -54,9 +54,6 @@ class ProxyRecordAndPlaybackSpec extends Specification {
 
 		then:
 		recorder.tape.size() == 1
-
-		cleanup:
-		recorder.tape.reset()
 	}
 
 	@Timeout(10)

src/test/groovy/co/freeside/betamax/proxy/RecordAndPlaybackProxyInterceptorSpec.groovy

@@ -50,7 +50,7 @@ class RecordAndPlaybackProxyInterceptorSpec extends Specification {
 		veto
 
 		and:
-		1 * tape.play(response)
+		1 * tape.play(request, response)
 	}
 
 	def "vetos a request and sets failing response code if no tape is inserted"() {

src/test/groovy/co/freeside/betamax/tape/ContentCharsetSpec.groovy

@@ -67,11 +67,11 @@ interactions:
 		def tape = YamlTape.readFrom(new StringReader(yaml))
 
 		and:
+		def request = new BasicRequest("GET", "http://freeside.co/betamax")
 		def response = new BasicResponse(HTTP_OK, "OK")
 
 		when:
-		tape.seek(new BasicRequest("GET", "http://freeside.co/betamax"))
-		tape.play(response)
+		tape.play(request, response)
 
 		then:
 		def expected = encoder ? encoder.encode("\u00a3", charset) : "\u00a3".getBytes(charset)

src/test/groovy/co/freeside/betamax/tape/ContentEncodingSpec.groovy

@@ -63,11 +63,11 @@ interactions:
 		def tape = YamlTape.readFrom(new StringReader(yaml))
 
 		and:
+		def request = new BasicRequest("GET", "http://freeside.co/betamax")
 		def response = new BasicResponse(200, "OK")
 
 		when:
-		tape.seek(new BasicRequest("GET", "http://freeside.co/betamax"))
-		tape.play(response)
+		tape.play(request, response)
 
 		then:
 		response.getHeader(CONTENT_ENCODING) == encoding

src/test/groovy/co/freeside/betamax/tape/MultiThreadedTapeAccessSpec.groovy

@@ -0,0 +1,59 @@
+package co.freeside.betamax.tape
+
+import co.freeside.betamax.Tape
+import co.freeside.betamax.proxy.Request
+import co.freeside.betamax.util.message.BasicRequest
+import co.freeside.betamax.util.message.BasicResponse
+import spock.lang.Issue
+import spock.lang.Shared
+import spock.lang.Specification
+
+import java.util.concurrent.CountDownLatch
+
+import static java.util.concurrent.TimeUnit.SECONDS
+
+@Issue('https://github.com/robfletcher/betamax/issues/57')
+class MultiThreadedTapeAccessSpec extends Specification {
+
+	@Shared Tape tape = new MemoryTape(name: 'multi_threaded_tape_access_spec')
+
+	void 'the correct response is replayed to each thread'() {
+		given: 'a number of requests'
+		List<Request> requests = (0..<threads).collect { i ->
+			def request = new BasicRequest('GET', "http://example.com/$i")
+			request.addHeader('X-Thread', i.toString())
+			request
+		}
+		println requests
+
+		and: 'some existing responses on tape'
+		requests.eachWithIndex { request, i ->
+			def response = new BasicResponse(status: 200, reason: 'OK', body: i.toString())
+			tape.record(request, response)
+		}
+
+		when: 'requests are replayed concurrently'
+		def finished = new CountDownLatch(threads)
+		def responses = [:]
+		requests.eachWithIndex { request, i ->
+			Thread.start {
+				def response = new BasicResponse()
+				tape.play(request, response)
+				responses[requests[i].getHeader('X-Thread')] = response.bodyAsText.text
+				finished.countDown()
+			}
+		}
+
+		then: 'all threads complete'
+		finished.await(1, SECONDS)
+
+		and: 'the correct response is returned to each request'
+		responses.every { key, value ->
+			key == value
+		}
+
+		where:
+		threads = 10
+	}
+
+}

src/test/groovy/co/freeside/betamax/tape/TapeSpec.groovy

@@ -30,13 +30,12 @@ class TapeSpec extends Specification {
 	}
 
 	def cleanup() {
-		tape.reset()
 		tape.mode = READ_WRITE
 	}
 
 	def "reading from an empty tape throws an exception"() {
 		when: "an empty tape is played"
-		tape.play(new BasicResponse())
+		tape.play(getRequest, new BasicResponse())
 
 		then: "an exception is thrown"
 		thrown IllegalStateException
@@ -63,9 +62,6 @@ class TapeSpec extends Specification {
 	}
 
 	def "can overwrite a recorded interaction"() {
-		given: "the tape is ready to play"
-		tape.seek(getRequest)
-
 		when: "a recording is made"
 		tape.record(getRequest, plainTextResponse)
 
@@ -93,11 +89,8 @@ class TapeSpec extends Specification {
 		given: "an http response to play back to"
 		def response = new BasicResponse()
 
-		and: "the tape is ready to play"
-		tape.seek(getRequest)
-
 		when: "the tape is played"
-		tape.play(response)
+		tape.play(getRequest, response)
 
 		then: "the recorded response data is copied onto the response"
 		response.status == plainTextResponse.status
@@ -119,30 +112,12 @@ class TapeSpec extends Specification {
 		interaction.request.body == request.bodyAsText.text
 	}
 
-	def "can reset the tape position"() {
-		given: "the tape is ready to read"
-		tape.seek(getRequest)
-
-		when: "the tape position is reset"
-		tape.reset()
-
-		and: "the tape is played"
-		tape.play(new BasicResponse())
-
-		then: "an exception is thrown"
-		def e = thrown(IllegalStateException)
-		e.message == "the tape is not ready to play"
-	}
-
 	def "a write-only tape cannot be read from"() {
 		given: "the tape is put into write-only mode"
 		tape.mode = WRITE_ONLY
 
-		and: "the tape is ready to read"
-		tape.seek(getRequest)
-
 		when: "the tape is played"
-		tape.play(new BasicResponse())
+		tape.play(getRequest, new BasicResponse())
 
 		then: "an exception is thrown"
 		def e = thrown(IllegalStateException)