feat: suffix fixture URLs with fixture IDs

BREAKING CHANGE: Before, a returned fixture URL looked like this

```
http://localhost:3000/api.github.com
```

All requests required a `X-Fixtures-Id` header set to the fixtures ID received before.

Now the Returned URL looks like this

```
http://localhost:3000/api.github.com/123fixturesid456
```

The `X-Fixtures-Id` header is now obsolete.

index.js

@@ -48,7 +48,7 @@ function fixtureServereMiddleware (options) {
 
     response.status(201).json({
       id,
-      url: urlResolve(state.fixturesUrl, urlParse(requestedFixture[0].scope).hostname)
+      url: urlResolve(state.fixturesUrl, urlParse(requestedFixture[0].scope).hostname + '/' + id)
     })
   })
 

lib/additions.js

@@ -3,14 +3,13 @@ module.exports = fixtureAdditions
 const mapValuesDeep = require('./map-values-deep')
 
 function fixtureAdditions (state, {id, fixture}) {
-  fixture.reqheaders['x-fixtures-id'] = id
   fixture = mapValuesDeep(fixture, value => {
     if (typeof value !== 'string') {
       return value
     }
 
-    // e.g. https://api.github.com/user -> http://localhost/api.github.com/user
-    return value.replace(/https?:\/\/([^/]+)\//, `${state.fixturesUrl}/$1/`)
+    // e.g. https://api.github.com/user -> http://localhost/api.github.com/fixturesid123/user
+    return value.replace(/https?:\/\/([^/]+)\//, `${state.fixturesUrl}/$1/${id}/`)
   })
 
   fixture.headers['content-length'] = String(calculateBodyLength(fixture.response))

lib/proxy.js

@@ -12,12 +12,12 @@ function proxy (state, {target}) {
   const middleware = express.Router()
   const hostname = urlParse(target).hostname
 
-  middleware.use(`/${hostname}`, validateRequest.bind(null, state), httpProxyMiddleware({
+  middleware.use(`/${hostname}/:fixturesId`, validateRequest.bind(null, state), httpProxyMiddleware({
     target: target,
     changeOrigin: true,
     logLevel: state.logLevel,
     pathRewrite: {
-      '^/[^/]+/': '/'
+      '^/[^/]+/[\\w]+/': '/'
     },
     onError (error, request, response) {
       /* istanbul ignore if */
@@ -48,11 +48,10 @@ function proxy (state, {target}) {
       }, null, 2) + '\n')
     },
     onProxyRes (proxyRes, request, response) {
-      const fixturesId = request.headers['x-fixtures-id']
-      const mock = state.cachimo.get(fixturesId)
+      const mock = state.cachimo.get(request.params.fixturesId)
       if (mock.isDone()) {
-        state.cachimo.remove(fixturesId)
-        state.log.debug(`Fixtures "${fixturesId}" completed`)
+        state.cachimo.remove(request.params.fixturesId)
+        state.log.debug(`Fixtures "${request.params.fixturesId}" completed`)
       }
     }
   }))

lib/request-validation-middleware.js

@@ -1,26 +1,19 @@
-module.exports = requireFixturesId
+module.exports = requestValidationMiddleware
 
 const urlParse = require('url').parse
 
-function requireFixturesId (state, req, res, next) {
-  if (!req.headers['accept']) {
-    return res.status(400).json({
+function requestValidationMiddleware (state, request, response, next) {
+  if (!request.headers['accept']) {
+    return response.status(400).json({
       error: 'Accept header required'
     })
   }
 
-  const fixturesId = req.headers['x-fixtures-id']
-  if (!fixturesId) {
-    return res.status(400).json({
-      error: 'X-Fixtures-Id header required'
-    })
-  }
-
-  const mock = state.cachimo.get(fixturesId)
+  const mock = state.cachimo.get(request.params.fixturesId)
 
   if (!mock) {
-    return res.status(404).json({
-      error: `Fixture "${fixturesId}" not found`
+    return response.status(404).json({
+      error: `Fixture "${request.params.fixturesId}" not found`
     })
   }
 
@@ -29,9 +22,9 @@ function requireFixturesId (state, req, res, next) {
   const nextFixtureMethod = nextFixture.split(' ')[0].toUpperCase()
   const nextFixturePath = urlParse(nextFixture.substr(nextFixtureMethod.length + 1)).pathname
 
-  if (req.method !== nextFixtureMethod || req.path !== nextFixturePath) {
-    return res.status(404).json({
-      error: `${req.method} ${req.path} does not match next fixture: ${nextFixtureMethod} ${nextFixturePath}`
+  if (request.method !== nextFixtureMethod || request.path !== nextFixturePath) {
+    return response.status(404).json({
+      error: `${request.method} ${request.path} does not match next fixture: ${nextFixtureMethod} ${nextFixturePath}`
     })
   }