`mock-api.config.js` can be configured to perform following tasks 1. Forward all requests to another API server(external_server_1) 2. Send custom request header in an API request (external_server_1) 3. Manipulate request before sending an API request 4. PATCH API call with variable in route 5. Send request to custom API server (external_server_2) 6. Set custom response 7. Set custom response status code ### Forward all requests to another API server(external_server_1) With following config you can send all requests to another API server. In this document, another API server is `https://jsonplaceholder.typicode.com` which is referred as external_server_1. ``` let config = { port: 3002, forward: { hostname: "https://jsonplaceholder.typicode.com", // hostname where request will be forwarded. This will be fallback for custom route. headers: { // headers to be sent in all requests. cookie: "pelUUID=96d2cfa0-e0ce-4795-beb3-917c5c1dd79c; _ga=GA1.2.1683668930.1598687051; _gcl_au=1.1.1869798560.1598687054; _fbp=fb.1.1598706524131.962812492;hl=en; pelUUID=174edf11de59da-068985a51643be-5b7f7327-5294d-174edf11de690c; __cfruid=e14408ee99e3a9ae0b2b1bcdfe71dda5c137e3a4-1601719873; WZRK_G=9746059b128d44d1bc23bec757dfb5c3; _gat=1; _gat_fabric=1; WZRK_S_8W6-695-WK5Z=%7B%22p%22%3A9%2C%22s%22%3A1601719832%2C%22t%22%3A1601720622%7D; modal_login=true", // cookie you would like to send as header when making request to your server(mentioned in hostname) host: "jsonplaceholder.typicode.com", accept: "application/json", referer: "https://jsonplaceholder.typicode.com/", "accept-encoding": "gzip" } } } ``` ### Send custom request header in an API request (external_server_1) Bellow config will forward POST request to `/posts` to `https://jsonplaceholder.typicode.com/posts` where only custom headers will be forwarded to `jsonplaceholder.typicode.com` server as `skip_forward_all_headers` and `skip_req_headers` are provided as true. ``` let config = { port: 3002, forward: { hostname: "https://jsonplaceholder.typicode.com", // hostname where request will be forwarded. This will be fallback for custom route. headers: { // headers to be sent in all requests. cookie: "pelUUID=96d2cfa0-e0ce-4795-beb3-917c5c1dd79c; _ga=GA1.2.1683668930.1598687051; _gcl_au=1.1.1869798560.1598687054; _fbp=fb.1.1598706524131.962812492;hl=en; pelUUID=174edf11de59da-068985a51643be-5b7f7327-5294d-174edf11de690c; __cfruid=e14408ee99e3a9ae0b2b1bcdfe71dda5c137e3a4-1601719873; WZRK_G=9746059b128d44d1bc23bec757dfb5c3; _gat=1; _gat_fabric=1; WZRK_S_8W6-695-WK5Z=%7B%22p%22%3A9%2C%22s%22%3A1601719832%2C%22t%22%3A1601720622%7D; modal_login=true", // cookie you would like to send as header when making request to your server(mentioned in hostname) host: "jsonplaceholder.typicode.com", accept: "application/json", referer: "https://jsonplaceholder.typicode.com/", "accept-encoding": "gzip" } }, routes: [{ enable_forward: true, request: { path: "/posts", method: "POST", payload: { title: 'foo' }, headers: { skip_forward_all_headers: true, skip_req_headers: true, "X-API-TOKEN": getAPIToken() } } }] } ``` > Please note that the only custom header for POST `/posts` route is `X-API-TOKEN`. No other headers will be forwarded with above configuration. ### Manipulate request before sending an API request We may want to update the request payload, query params, headers before actually being sent to our API server from `moc-api` server. To achieve this we can utilise `beforeRequest` method of route. In each route, we can define `beforeRequest` method which provides us access to your route's `request` object before the request was made. In this function, we can manipulate the request object. The `this` object inside `beforeRequest` funtion, refers to route's `request` object. In also provides access to request's `params` and `payload`. ``` let config = { port: 3002, forward: { hostname: "https://jsonplaceholder.typicode.com", // hostname where request will be forwarded. This will be fallback for custom route. headers: { // headers to be sent in all requests. cookie: "pelUUID=96d2cfa0-e0ce-4795-beb3-917c5c1dd79c; _ga=GA1.2.1683668930.1598687051; _gcl_au=1.1.1869798560.1598687054; _fbp=fb.1.1598706524131.962812492;hl=en; pelUUID=174edf11de59da-068985a51643be-5b7f7327-5294d-174edf11de690c; __cfruid=e14408ee99e3a9ae0b2b1bcdfe71dda5c137e3a4-1601719873; WZRK_G=9746059b128d44d1bc23bec757dfb5c3; _gat=1; _gat_fabric=1; WZRK_S_8W6-695-WK5Z=%7B%22p%22%3A9%2C%22s%22%3A1601719832%2C%22t%22%3A1601720622%7D; modal_login=true", // cookie you would like to send as header when making request to your server(mentioned in hostname) host: "jsonplaceholder.typicode.com", accept: "application/json", referer: "https://jsonplaceholder.typicode.com/", "accept-encoding": "gzip" } }, routes: [{ enable_forward: true, request: { path: "/posts", method: "POST", payload: { title: 'foo' }, headers: { skip_forward_all_headers: true, skip_req_headers: true, "X-API-TOKEN": getAPIToken() }, beforeRequest: function ({params, body}) { // console.log("this", this); const getProfileToken = () => 'YYYYY'; this.headers["X-PROFILE-TOKEN"] = getProfileToken() } } }] } ``` In the above configuration, `beforeRequest` method updates route request's headers to add `X-PROFILE-TOKEN` on this fly before request actually being sent to the API server. The above configuration, sends following headers while making POST request to `https://jsonplaceholder.typicode.com/posts` ``` headers { 'X-API-TOKEN': { 'X-API-TOKEN': 'XXXXXXXX' }, 'X-PROFILE-TOKEN': 'YYYYY' } ``` ### PATCH API call with variable in route We can pass variable in route as params. `path` variable inside `request` object follows [express route](https://expressjs.com/en/guide/routing.html) pattern. ``` let config = { port: 3002, forward: { hostname: "https://jsonplaceholder.typicode.com", // hostname where request will be forwarded. This will be fallback for custom route. headers: { // headers to be sent in all requests. cookie: "pelUUID=96d2cfa0-e0ce-4795-beb3-917c5c1dd79c; _ga=GA1.2.1683668930.1598687051; _gcl_au=1.1.1869798560.1598687054; _fbp=fb.1.1598706524131.962812492;hl=en; pelUUID=174edf11de59da-068985a51643be-5b7f7327-5294d-174edf11de690c; __cfruid=e14408ee99e3a9ae0b2b1bcdfe71dda5c137e3a4-1601719873; WZRK_G=9746059b128d44d1bc23bec757dfb5c3; _gat=1; _gat_fabric=1; WZRK_S_8W6-695-WK5Z=%7B%22p%22%3A9%2C%22s%22%3A1601719832%2C%22t%22%3A1601720622%7D; modal_login=true", // cookie you would like to send as header when making request to your server(mentioned in hostname) host: "jsonplaceholder.typicode.com", accept: "application/json", referer: "https://jsonplaceholder.typicode.com/", "accept-encoding": "gzip" } }, routes: [{ enable_forward: true, request: { path: "/posts/:post_id", method: "PATCH", payload: { title: 'foo' }, headers: { skip_forward_all_headers: true, skip_req_headers: true, "X-API-TOKEN": getAPIToken() }, beforeRequest: function ({params, body}) { // console.log("this", this); // console.log("params, body", params, body); let {post_id} = params; const getProfileToken = () => 'YYYYY'; this.payload.post_multiplier = 2*post_id; this.headers["X-PROFILE-TOKEN"] = getProfileToken() } }, response: { status: 206, response_data: { "Name":"Keshav Kumar", "userId":1, "githubHandle":"rnmkeshav" }, } }] } ``` In the above config, makes a PATCH request to `https://jsonplaceholder.typicode.com/posts/1`. Above configuration also usage `beforeRequest` to manipulate `headers` as well as `payload` before sending request. ### Send request to custom API server (external_server_2) When we specify `hostname` in route object, it does not use forward config i.e `config.forward` but usage provided hostname. ``` let config = { port: 3002, forward: { hostname: "https://jsonplaceholder.typicode.com", // hostname where request will be forwarded. This will be fallback for custom route. headers: { // headers to be sent in all requests. cookie: "pelUUID=96d2cfa0-e0ce-4795-beb3-917c5c1dd79c; _ga=GA1.2.1683668930.1598687051; _gcl_au=1.1.1869798560.1598687054; _fbp=fb.1.1598706524131.962812492;hl=en; pelUUID=174edf11de59da-068985a51643be-5b7f7327-5294d-174edf11de690c; __cfruid=e14408ee99e3a9ae0b2b1bcdfe71dda5c137e3a4-1601719873; WZRK_G=9746059b128d44d1bc23bec757dfb5c3; _gat=1; _gat_fabric=1; WZRK_S_8W6-695-WK5Z=%7B%22p%22%3A9%2C%22s%22%3A1601719832%2C%22t%22%3A1601720622%7D; modal_login=true", // cookie you would like to send as header when making request to your server(mentioned in hostname) host: "jsonplaceholder.typicode.com", accept: "application/json", referer: "https://jsonplaceholder.typicode.com/", "accept-encoding": "gzip" } }, routes: [{ // To see this in action, make a POST request to `http://localhost:3002/api/users` with {"name":"morpheus","job":"leader"} as request payload enable_forward: true, request: { path: "/api/users", method: "POST", hostname: "https://reqres.in/", payload: {}, headers: { skip_req_headers: true, //headers which gets sent automatically from client/browser skip_forward_all_headers: true, //headers which gets sent in forward all request. `config.forward.headers` // host: "https://reqres.in", accept: "application/json", // referer: "https://reqres.in/", // "accept-encoding": "gzip", // 'Content-type': "application/json" } } }] } ``` The above configuration will send all POST requests routed to `/api/users` to `https://reqres.in/api/users` route. ### Set custom response By setting `config.routes.response.response_data` we can set our own custom response data for a requested route path. This will override any response coming from external API server(`https://jsonplaceholder.typicode.com` in this case) ``` let config = { port: 3002, forward: { hostname: "https://jsonplaceholder.typicode.com", // hostname where request will be forwarded. This will be fallback for custom route. headers: { // headers to be sent in all requests. cookie: "pelUUID=96d2cfa0-e0ce-4795-beb3-917c5c1dd79c; _ga=GA1.2.1683668930.1598687051; _gcl_au=1.1.1869798560.1598687054; _fbp=fb.1.1598706524131.962812492;hl=en; pelUUID=174edf11de59da-068985a51643be-5b7f7327-5294d-174edf11de690c; __cfruid=e14408ee99e3a9ae0b2b1bcdfe71dda5c137e3a4-1601719873; WZRK_G=9746059b128d44d1bc23bec757dfb5c3; _gat=1; _gat_fabric=1; WZRK_S_8W6-695-WK5Z=%7B%22p%22%3A9%2C%22s%22%3A1601719832%2C%22t%22%3A1601720622%7D; modal_login=true", // cookie you would like to send as header when making request to your server(mentioned in hostname) host: "jsonplaceholder.typicode.com", accept: "application/json", referer: "https://jsonplaceholder.typicode.com/", "accept-encoding": "gzip" } }, routes: [{ enable_forward: true, request: { path: "/posts", method: "POST", payload: { title: 'foo' }, headers: { skip_forward_all_headers: true, skip_req_headers: true, "X-API-TOKEN": getAPIToken() } }, response: { response_data: { "Name":"Keshav Kumar", "userId":1, "githubHandle":"rnmkeshav" }, } }] } ``` With above configuration, the response to POST `https://jsonplaceholder.typicode.com/posts` will always be following: ``` { "Name":"Keshav Kumar", "userId":1, "githubHandle":"rnmkeshav" } ``` ### Set custom response status code To set custom response status code, we need to add desired status code in `status` key of `config.routes.response.status`. In the above example if we add `status` key to response object. The individual route object will look as follows ``` { enable_forward: true, request: { path: "/posts", method: "POST", payload: { title: 'foo' }, headers: { skip_forward_all_headers: true, skip_req_headers: true, "X-API-TOKEN": getAPIToken() } }, response: { status: 206 } } ``` In the above config, we have set `response.status` as 206. So POST API request to `https://jsonplaceholder.typicode.com/posts` will always respond with status code of 206.