redux-saga-requests

Redux-Saga addon to simplify handling of AJAX requests. It supports Axios and Fetch API, but different integrations could be added, as they are implemented in a plugin fashion.

Table of content

• Motivation
• Installation
• Usage
• Actions
• Reducers
• Interceptors
• FSA
• Promise middleware
• Usage with Fetch API
• Examples

Motivation ⬆️

With redux-saga-requests, assuming you use axios you could refactor a code in the following way:

  import axios from 'axios';
- import { takeEvery, put, call } from 'redux-saga/effects';
+ import { createRequestInstance, watchRequests, requestsReducer } from 'redux-saga-requests';
+ import axiosDriver from 'redux-saga-requests-axios';

  const FETCH_BOOKS = 'FETCH_BOOKS';
- const FETCH_BOOKS_SUCCESS = 'FETCH_BOOKS_SUCCESS';
- const FETCH_BOOKS_ERROR = 'FETCH_BOOKS_ERROR';

- const fetchBooks = () => ({ type: FETCH_BOOKS });
- const fetchBooksSuccess = data => ({ type: FETCH_BOOKS_SUCCESS, data });
- const fetchBooksError = error => ({ type: FETCH_BOOKS_ERROR, error });
+ const fetchBooks = () => ({
+   type: FETCH_BOOKS,
+   request: {
+     url: '/books',
+     // you can put here other Axios config attributes, like method, data, headers etc.
+   },
+ });

- const defaultState = {
-   data: null,
-   pending: 0, // number of pending FETCH_BOOKS requests
-   error: null,
- };
-
- const booksReducer = (state = defaultState, action) => {
-   switch (action.type) {
-     case FETCH_BOOKS:
-       return { ...defaultState, pending: state.pending + 1 };
-     case FETCH_BOOKS_SUCCESS:
-       return { ...defaultState, data: action.data, pending: state.pending - 1 };
-     case FETCH_BOOKS_ERROR:
-       return { ...defaultState, error: action.error, pending: state.pending - 1 };
-     default:
-       return state;
-   }
- };
+ const booksReducer = requestsReducer({ actionType: FETCH_BOOKS });

- const fetchBooksApi = () => axios.get('/books');
-
- function* fetchBooksSaga() {
-   try {
-     const response = yield call(fetchBooksApi);
-     yield put(fetchBooksSuccess(response.data));
-   } catch (e) {
-     yield put(fetchBooksError(e));
-   }
- }
-
  function* rootSaga() {
-   yield takeEvery(FETCH_BOOKS, fetchBooksSaga);
+   yield createRequestInstance(axios, { driver: axiosDriver });
+   yield watchRequests();
  }

With redux-saga-requests, you no longer need to define error and success actions to do things like error handling or showing loading spinners. You don't need to write requests related repetitive sagas and reducers either.

Here you can see the list of features this library provides:

• you define your AJAX requests as simple actions, like { type: FETCH_BOOKS, request: { url: '/books' } } and success, error (abort is also supported, see below) actions will be dispatched automatically for you
• success, error and abort functions, which add correct and consistent suffixes to your request action types (check low-level-reducers example to see how to use those functions in your reducers)
• requestsReducer higher order reducer, which takes requests related state management burden from your shoulders
• automatic request abort - when a saga is cancelled, a request made by it is automatically aborted and an abort action is dispatched (especially handy with takeLatest and race Redux-Saga effects)
• sending multiple requests in one action - { type: FETCH_BOOKS_AND_AUTHORS, request: [{ url: '/books' }, { url: '/authors}'] } will send two requests and wrap them in Promise.all
• flexibility - you can use "auto mode" watchRequests (see basic example), or lower level sendRequest (see advanced example), or... you could even access your request instance with getRequestInstance
• support for Axios and Fetch API - additional clients could be added, you could even write your own client integration as a driver (see ./packages/redux-saga-requests-axios/src/axios-driver.js for the example)
• compatible with FSA, redux-act and redux-actions libraries (see redux-act example)
• simple to use with server side rendering - for example you could pass Axios instance to createRequestInstance and you don't need to worry that Axios interceptors would be shared across multiple requests
• onRequest, onSuccess, onError and onAbort interceptors, you can attach your sagas (or simple functions) to them to define a global behaviour for a given event type
• optional requestsPromiseMiddleware, which promisifies requests actions dispatch, so you can wait in your react components to get request response, the same way like you can do this with redux-thunk

Installation ⬆️

To install the package, just run:

$ yarn add redux-saga-requests

or...

$ npm install redux-saga-requests

or you can just use CDN: https://unpkg.com/redux-saga-requests.

Also, you need to install a driver:

• if you use Axios, install axios and redux-saga-requests-axios:

  $ yarn add axios redux-saga-requests-axios
  

  or...

  $ npm install axios redux-saga-requests-axios
  

  or CDN: https://unpkg.com/redux-saga-requests-axios.

• if you use Fetch API, install isomorphic-fetch (or a different Fetch polyfill) and redux-saga-requests-fetch:

  $ yarn add isomorphic-fetch redux-saga-requests-fetch
  

  or...

  $ npm install isomorphic-fetch redux-saga-requests-fetch
  

  or CDN: https://unpkg.com/redux-saga-requests-fetch.

Of course, because this is Redux-Saga addon, you also need to install Redux-Saga.

Usage ⬆️

For a basic usage, see Motivation paragraph.

watchRequests

As you probably guessed, the most job is done by watchRequests, which is like a manager to your request actions - it sends requests you define in your actions and dispatches success, error and abort actions, depending on the outcome. It can also automatically abort requests. Aborting requests is a very important, but often neglected topic. Lets say you have a paginated list and a user asked for 1st page, then 2nd and lets assume response for 1st one will come later. Or... lets say a private data are being fetched and before this request is finished a user logged out. You could introduce many race condition bugs like this, without even realizing - they won't happen on your local machine (without throthling in your browser), but they could happen on a production system, especially on a slow mobile internet, with a high latency. Because aborting is so important, you can pass a config to watchRequests to adjust, how different actions will be aborted. This config has following attributes:

• abortOn: string | string[] | action => boolean: allows you to define actions, on which requests should be aborted, has the same form which you can pass to redux-saga take effect, for example 'LOGOUT', ['LOGOUT'], action => action.type === 'LOGOUT', default is null
• takeLatest: boolean | action => boolean: if true, when a new request will be dispatched while a pending of the same type is still running, the previous one will be automatically aborted, default is true for GET requests and false for the rest ones
• getLastActionKey: action => string: a key generator to match actions of the same type, typically you won't need to adjust it, but it might come in handy when you want some actions with the same type to be treated as a different one, default is action => action.type.

So, for instance, you could do this:

yield watchRequests({
  takeLatest: false,
  abortOn: 'LOGOUT',
});

Above defines a global behaviour, but what if you want to have different settings for different actions? You can use the same config to adjust them per action type:

yield watchRequests(
  { abortOn: 'LOGOUT' },
  {
    SAVE_STH_AND_DONT_ABORT_ACTION_WHEN_MULTIPLE: { takeLatest: false }
  }
);

Above will merge settings for SAVE_STH_AND_DONT_ABORT_ACTION_WHEN_MULTIPLE action with global ones, resulting in { takeLatest: false, abortOn: 'LOGOUT' } for SAVE_STH_AND_DONT_ABORT_ACTION_WHEN_MULTIPLE, and { takeLatest: true, abortOn: 'LOGOUT' } for the rest.

Also, if you like the default behaviour, but just wanna change it for some actions, you can pass 1st param as null:

yield watchRequests(
  null,
  {
    SAVE_STH_AND_DONT_ABORT_ACTION_WHEN_MULTIPLE: { takeLatest: false }
  }
);

Last, but not least, remember that watchRequests is a blocking effect, so if you have more sagas, use yield fork(watchRequests), or wrap it with something else in all:

import { all, takeLatest, put } from 'redux-saga/effects';
import { createRequestInstance, watchRequests, success } from 'redux-saga-requests';
import axiosDriver from 'redux-saga-requests-axios';

function* fetchBooksSuccessSaga() {
  yield put(addMessage('Books have been loaded');
}

function* rootSaga() {
  yield createRequestInstance(axios, { driver: axiosDriver });
  yield all([
    watchRequests(), // put it before other sagas which handle requests, otherwise watchRequests might miss some requests
    takeLatest(success('FETCH_BOOK'), fetchBooksSuccessSaga),
  ]);
}

sendRequest

Under the hood, watchRequests uses a lower level sendRequest. watchRequests should be flexible enough, so you won't need to worry about sendRequest, but it is useful to know about it, it is handy in Interceptors. Also, if you don't like the magic of watchRequests, you might use it everywhere, or... you could write your own watchRequests!. This is how it works:

import axios from 'axios';
import { takeLatest } from 'redux-saga/effects';
import { createRequestInstance, sendRequest } from 'redux-saga-requests';
import axiosDriver from 'redux-saga-requests-axios'; // or a different driver

const FETCH_BOOKS = 'FETCH_BOOKS';

const fetchBooks = () => ({
  type: FETCH_BOOKS,
  request: { url: '/books' },
});

function* rootSaga() {
  yield createRequestInstance(axios, { driver: axiosDriver });
  yield takeLatest(FETCH_POST, sendRequest);
}

Now, if /books request is pending and another fetchPost action is triggered, the previous request will be aborted and FETCH_BOOKS_ABORT will be dispatched. Please note, that requests aborts are working only for axios driver, request cannot be really aborted for Fetch API according to their specifications, at least not yet, but you won't notice it in your application (apart from unnecessary request overhead) - FETCH_BOOKS_ABORT actions will still be fired.

You could also use race effect:

import axios from 'axios';
import { call, race, take, takeLatest } from 'redux-saga/effects';
import { createRequestInstance, sendRequest } from 'redux-saga-requests';
import axiosDriver from 'redux-saga-requests-axios'; // or a different driver

const FETCH_BOOKS = 'FETCH_BOOKS';
const CANCEL_REQUEST = 'CANCEL_REQUEST';

const fetchBooks = () => ({
  type: FETCH_BOOKS,
  request: { url: '/books' },
});

const cancelRequest = () => ({ type: CANCEL_REQUEST });

function* fetchBookSaga(fetchBookAction) {
  yield race([
    call(sendRequest, fetchBookAction),
    take(CANCEL_REQUEST),
  ]);
}

function* rootSaga() {
  yield createRequestInstance(axios, { driver: axiosDriver });
  yield takeLatest(FETCH_BOOKS, fetchBookSaga);
}

In above case, not only the last /books request could be successful, but also it could be aborted with cancelRequest action, as sendRequest would be aborted as it would lose with take(CANCEL_REQUEST) effect.

Of course, you can send requests directly also from your sagas:

function* fetchBookSaga() {
  const { response, error } = yield call(
    sendRequest,
    fetchBooks(),
    { dispatchRequestAction: true },
  );

  if (response) {
    // do sth with response
  } else {
    // do sth with error
  }
}

The key here is, that you need to pass { dispatchRequestAction: true } as second argument to sendRequest, so that fetchBooks action will be dispatched - usually it is already dispatched somewhere else (from your React components onClick for instance), but here not, so we must explicitely tell sendRequest to dispatch it.

getRequestInstance

Also, it is possible to get access to your request instance (like Axios) in your Saga:

import { getRequestInstance } from 'redux-saga-requests';

function* fetchBookSaga() {
  const requestInstance = yield getRequestInstance();
  /* now you can do whatever you want, for example, if u use axios:
  const response = yield call(requestInstance.get, '/some-url') */
}

You can do whatever you want with it, which gives you maximum flexibility. Typically it is useful in Interceptors, when you want to make some request directly, without using redux action - for redux action you would use sendRequest.

Actions ⬆️

No matter whether you use watchRequests or sendRequest, you only need to define request actions, which will trigger AJAX calls for you, as well as dispatch success, error or abort actions. Lets say you defined a following request action:

const fetchBooks = (id) => ({
  type: 'DELETE_BOOK',
  request: {
    url: `/books/${id}`,
    method: 'delete'
  },
  meta: { // meta is optional, it will be added to success, error or abort action when defined
    id,
  },
});

With this request action, assuming id = 1, following actions will be dispatched, depending on the request outcome:

Successful response

{
  type: 'DELETE_BOOK_SUCCESS',
  data: 'a server response',
  meta: {
    id: 1, // got from request action meta
    requestAction: {
      type: 'DELETE_BOOK',
      request: {
        url: '/books/1',
        method: 'delete'
      },
      meta: {
        id: 1,
      },
    },
  },
}

Error response

{
  type: 'DELETE_BOOK_ERROR',
  error: 'a server error',
  meta: {
    id: 1, // got from request action meta
    requestAction: {
      type: 'DELETE_BOOK',
      request: {
        url: '/books/1',
        method: 'delete'
      },
      meta: {
        id: 1,
      },
    },
  },
}

Aborted request

{
  type: 'DELETE_BOOK_ABORT',
  meta: {
    id: 1, // got from request action meta
    requestAction: {
      type: 'DELETE_BOOK',
      request: {
        url: '/books/1',
        method: 'delete'
      },
      meta: {
        id: 1,
      },
    },
  },
}

Custom actions

If you don't like the way how success, error and abort are structured, it is possible to adjust them. You can change _SUCCESS, _ERROR and _ABORT default suffixes with success, error and abort in createRequestInstance config:

import axios from 'axios';
import { getActionWithSuffix, watchRequests, createRequestInstance, createRequestsReducer } from 'redux-saga-requests';
import axiosDriver from 'redux-saga-requests-axios'; // or a different driver

const success = getActionWithSuffix('MY_SUCCESS_SUFFIX');
const error = getActionWithSuffix('MY_ERROR_SUFFIX');
const abort = getActionWithSuffix('MY_ABORT_SUFFIX');

function* rootSaga() {
  yield createRequestInstance(axios, {
    driver: axiosDriver,
    success,
    error,
    abort,
  });
  yield watchRequests();
}

If you need even more control, you can define how the rest of actions payloads look like by passing successAction, errorAction, abortAction, for example:

const successAction = (action, data) => ({
  responseData: data,
  meta: {
    requestAction: action,
  },
});

function* rootSaga() {
  yield createRequestInstance(axios, {
    driver: axiosDriver,
    successAction,
  });
  yield watchRequests();
}

Reducers ⬆️

Except for watchRequests and sendRequest, which can simplify your actions and sagas a lot, you can also use requestsReducer, a higher order reducer, which is responsible for a portion of your state related to a given request type. For a general idea how it works, see Motivation paragraph. This is just a minimal example, where with simple:

const reducer = requestsReducer({ actionType: `FETCH_SOMETHING` });

you already have a working reducer which will handle FETCH_SOMETHING, FETCH_SOMETHING_SUCCESS, FETCH_SOMETHING_ERROR and FETCH_SOMETHING_ABORT actions, updating a following state attributes for you:

• data: here a data from your API will be kept, updated after FETCH_SOMETHING_SUCCESS is dispatched, initially set to null (default) or [], depending on multiple config attribute (see below)
• error: initially null, updated to a HTTP error after FETCH_SOMETHING_ERROR is dispatched
• pending: number of pending FETCH_SOMETHING requests, initially 0, incremented by 1 for each FETCH_SOMETHING, and decremented by 1 for each of FETCH_SOMETHING_SUCCESS, FETCH_SOMETHING_ERROR, FETCH_SOMETHING_ABORT (implemeted as integer, not boolean due to possibility of multiple pending requests of the same type - for example in a sequence FETCH_SOMETHING, FETCH_SOMETHING, FETCH_SOMETHING_SUCCESS we would set pending to false, despite the fact 2nd FETCH_SOMETHING is still running, with integer pending will be set to 1, which for example allows you to easily write a selector like showSpinner = pending => pending > 0)

In order to be flexible, apart from actionType passed in requestsReducer config, optionally you can pass any of following attributes:

• multiple: boolean: default to false, change it to true if you want your not loaded data to be stored as [] instead of null
• dataKey: string: default to 'data', change it, if for some reason you want your data to be kept in a different key
• errorKey: string: default to 'error', change it, if for some reason you want your errors to be kept in a different key
• pendingKey: string: default to 'pending', change it, if for some reason you want your pending state to be kept in a different key
• getData: (state, action, config) => data: describes how to get data from action object, returns action.data or action.payload.data when action is FSA compliant
• getError: (state, action, config) => data: describes how to get error from action object, returns action.error or action.payload when action is FSA compliant
• onRequest: (state, action, config) => nextState: here you can adjust how requestReducers handles request actions
• onSuccess: (state, action, config) => nextState: here you can adjust how requestReducers handles success actions
• onError: (state, action, config) => nextState: here you can adjust how requestReducers handles error actions
• onAbort: (state, action, config) => nextState: here you can adjust how requestReducers handles abort actions
• success: (actionType: string) => string: override when using not standard success action suffix, handles _SUCCESS as a default
• error: (actionType: string) => string: override when using not standard error action suffix, handles _ERROR as a default
• abort: (actionType: string) => string: override when using not standard abort action suffix, handles _ABORT as a default
• resetOn: action => boolean or string[]: callback or array of action types on which reducer will reset its state to initial one, for instance ['LOGOUT'] or action => action.type === 'TYPE', [] as a default

For example:

const reducer = requestsReducer({ actionType: `FETCH_SOMETHING`, multiple: true });

which will keep your empty data as [], not null.

For inspiration how you could override any of those attributes, see default config source.

You might also want to adjust any configuration for all your requests reducers globally. Here is how you can do this:

import { createRequestsReducer } from 'redux-saga-requests';

const requestsReducer = createRequestsReducer({ errorKey: 'fail' });

Now, instead of built-in requestsReducer, you can use your own one, and from now on all errors will be kept in fail key in your state, not error.

If you need to have an additional state next to built-in state in requestsReducer, or additional actions you would like it to handle, you can pass an optional custom reducer as a 2nd pararameter to requestsReducer:

const activeReducer = (state = { active: false }, action) => {
  switch (action.type) {
    case `SET_ACTIVE`:
      return { ...state, active: true };
    case `SET_INACTIVE`:
      return { ...state, active: false };
    default:
      return state;
  }

const reducer = requestsReducer({ actionType }, activeReducer);

which effectively will merge activeReducer with requestsReducer, giving you initial state:

const state = {
  data: null,
  error: null,
  pending: 0,
  active: false,
};

Basically, you can use requestsReducer, which will handle requests related logic in a configurable way with any custom logic you need.

However, if requestsReducer seems too magical for you, this is totally fine, you can write your reducers in a standard way too, but you might consider using success, error and abort helpers, which can add proper suffixes for you:

import { success, error, abort } from 'redux-saga-requests';

const initialState = {
  data: null,
  fetching: false,
  error: false,
};

const FETCH_BOOKS = 'FETCH_BOOKS';

const booksReducer = (state = initialState, action) => {
  switch (action.type) {
    case FETCH_BOOKS:
      return { ...initialState, fetching: true };
    case success(FETCH_BOOKS):
      return {
        ...initialState,
        data: { ...action.data },
      };
    case error(FETCH_BOOKS):
      return { ...initialState, error: true };
    case abort(FETCH_BOOKS):
      return { ...initialState, fetching: false };
    default:
      return state;
  }
};

Interceptors ⬆️

You can add global handlers to onRequest, onSuccess, onError add onAbort, like so:

import { sendRequest, getRequestInstance } from 'redux-saga-requests';

function* onRequestSaga(request, action) {
  // do sth with you request, like add token to header, or dispatch some action etc.
  return request;
}

function* onResponseSaga(response, action) {
  // do sth with the response, dispatch some action etc
  return response;
}

function* onErrorSaga(error, action) {
  // do sth here, like dispatch some action

  // you must return { error } in case you dont want to catch error
  // or { error: anotherError }
  // or { response: someRequestResponse } if you want to recover from error

  if (tokenExpired(error)) {
    // get driver instance, in our case Axios to make a request without Redux
    const requestInstance = yield getRequestInstance();

    try {
      // trying to get a new token
      const { data } = yield call(
        requestInstance.post,
        '/refreshToken',
      );

      saveNewToken(data.token); // for example to localStorage

      // we fire the same request again:
      // - with silent: true not to dispatch duplicated actions
      // - with runOnError: false not to call this interceptor again for this request
      return yield call(sendRequest, action, { silent: true, runOnError: false });

      /* above is a handy shortcut of doing
      const { response, error } = yield call(
        sendRequest,
        action,
        { silent: true, runOnError: false },
      );

      if (response) {
        return { response };
      } else {
        return { error };
      } */
    } catch(e) {
      // we didnt manage to get a new token
      return { error: e }
    }
  }

  // not related token error, we pass it like nothing happened
  return { error };
}

function* onAbortSaga(action) {
  // do sth, for example an action dispatch
}

function* rootSaga() {
  yield createRequestInstance(axios, {
    driver: axiosDriver,
    onRequest: onRequestSaga,
    onSuccess: onResponseSaga,
    onError: onErrorSaga,
    onAbort: onAbortSaga,
  });
  yield watchRequest();
}

FSA ⬆️

If you like your actions to be compatible with Flux Standard Action, that's totally fine, you can define your request actions like:

const fetchBooks = () => ({
  type: 'FETCH_BOOKS',
  payload: {
    request: {
      url: '/books',
    },
  },
  meta: { // optional
    someKey: 'someValue',
  },
});

Then, success, error and abort actions will also be FSA compliant. Moreover, requestsReducer will also correctly handle FSA actions. For details, see redux-act example.

Promise middleware ⬆️

One disadvantage of using sagas is that there is no way to dispatch an action which triggets a saga from React component and wait for this saga to complete. Because of this, integration with libraries like Formik are sometimes harder - for example you are forced to push some callbacks to Redux actions for a saga to execute later, which is not convenient. Thats why this library gives an optional requestsPromiseMiddleware:

import { createStore, applyMiddleware } from 'redux';
import createSagaMiddleware from 'redux-saga';
import { requestsPromiseMiddleware } from 'redux-saga-requests';

const sagaMiddleware = createSagaMiddleware();
const store = createStore(
  app,
  initialState,
  applyMiddleware(requestsPromiseMiddleware(), sagaMiddleware),
);

Now, lets say you defined an action:

const fetchBooks = () => ({
  type: FETCH_BOOKS,
  request: { url: '/books'},
  meta: {
    asPromise: true,
  },
});

You can dispatch the action from a component and wait for a response:

class Books extends Component {
  fetch = () => {
    this.props.fetchBooks().then(successAction => {
      // handle successful response
    }).catch(errorOrAbortAction => {
      // handle error or aborted request
    })
  }

  render() {
    // ...
  }
}

If you adjusted how response actions are structured, you might need to configure this middleware to fit your settings by passing an optional config to requestsPromiseMiddleware:

requestsPromiseMiddleware({
  success: customSuccessFunction,
  auto: true // if you with to promisify all request actions without explicit meta.asPromise true
  getRequestAction = action => action.meta && action.meta.requestAction ? action.meta.requestAction : null, // default
})

Usage with Fetch API ⬆️

All of the above examples show Axios usage, in order to use Fetch API, use below snippet:

import 'isomorphic-fetch'; // or a different fetch polyfill
import { createRequestInstance, watchRequests } from 'redux-saga-requests';
import fetchDriver from 'redux-saga-requests-fetch';

function* rootSaga() {
  yield createRequestInstance(
    window.fetch,
    {
      driver: fetchDriver,
      baseURL: 'https://my-domain.com' // optional - it works like axios baseURL, prepending all relative urls
      AbortController: window.AbortController, // optional, if your browser supports AbortController or you use a polyfill like https://github.com/mo/abortcontroller-polyfill
    },
  );
  yield watchRequests();
}

And in order to create Fetch API requests, below:

fetch('/users', {
  method: 'POST',
  body: JSON.stringify(data),
  headers: {
    'Content-Type': 'application/json',
  },
});

should be translated to this:

const fetchUsers = () => ({
  type: 'FETCH_USERS',
  request: {
    url: '/users/',
    method: 'POST',
    body: JSON.stringify(data),
    headers: {
      'Content-Type': 'application/json',
    },
  }
});

The point is, you can use the same request config like you do with pure Fetch API, but you need to pass url in the config itself. Also, one additional parameter you could provide in the config is responseType, which is set as json as the default. Available response types are: 'arraybuffer', 'blob', 'formData', 'json', 'text', or null (if you don't want a response stream to be read for the given response).

Also, this driver reads response streams automatically for you (depending on responseType you choose) and sets it as response.data, so instead of doing response.json(), just read response.data.

Examples ⬆️

I highly recommend to try examples how this package could be used in real applications. You could play with those demos and see what actions are being sent with redux-devtools.

There are following examples currently:

• basic
• advanced
• Fetch API
• redux-act integration
• low-level-reducers

Credits ⬆️

This library was inspired by redux-axios-middleware (I highly recommend this library if someone doesn't use Redux-Saga!) and issue in Redux-Saga, when it was recommended not to combine another async middleware with sagas.

Licence ⬆️

MIT