示例:Reddit API

2018-02-24 15:28 更新

示例:Reddit API

这是一个高级教程的例子,包含使用 Reddit API 请求文章标题的全部源码。

入口

index.js

import 'babel-core/polyfill';

import React from 'react';
import Root from './containers/Root';

React.render(
  <Root />,
  document.getElementById('root')
);

Action Creators and Constants

actions.js

import fetch from 'isomorphic-fetch';

export const REQUEST_POSTS = 'REQUEST_POSTS';
export const RECEIVE_POSTS = 'RECEIVE_POSTS';
export const SELECT_REDDIT = 'SELECT_REDDIT';
export const INVALIDATE_REDDIT = 'INVALIDATE_REDDIT';

export function selectReddit(reddit) {
  return {
    type: SELECT_REDDIT,
    reddit
  };
}

export function invalidateReddit(reddit) {
  return {
    type: INVALIDATE_REDDIT,
    reddit
  };
}

function requestPosts(reddit) {
  return {
    type: REQUEST_POSTS,
    reddit
  };
}

function receivePosts(reddit, json) {
  return {
    type: RECEIVE_POSTS,
    reddit: reddit,
    posts: json.data.children.map(child => child.data),
    receivedAt: Date.now()
  };
}

function fetchPosts(reddit) {
  return dispatch => {
    dispatch(requestPosts(reddit));
    return fetch(`http://www.reddit.com/r/${reddit}.json`)
      .then(req => req.json())
      .then(json => dispatch(receivePosts(reddit, json)));
  }
}

function shouldFetchPosts(state, reddit) {
  const posts = state.postsByReddit[reddit];
  if (!posts) {
    return true;
  } else if (posts.isFetching) {
    return false;
  } else {
    return posts.didInvalidate;
  }
}

export function fetchPostsIfNeeded(reddit) {
  return (dispatch, getState) => {
    if (shouldFetchPosts(getState(), reddit)) {
      return dispatch(fetchPosts(reddit));
    }
  };
}

Reducers

reducers.js

import { combineReducers } from 'redux';
import {
  SELECT_REDDIT, INVALIDATE_REDDIT,
  REQUEST_POSTS, RECEIVE_POSTS
} from '../actions';

function selectedReddit(state = 'reactjs', action) {
  switch (action.type) {
  case SELECT_REDDIT:
    return action.reddit;
  default:
    return state;
  }
}

function posts(state = {
  isFetching: false,
  didInvalidate: false,
  items: []
}, action) {
  switch (action.type) {
  case INVALIDATE_REDDIT:
    return Object.assign({}, state, {
      didInvalidate: true
    });
  case REQUEST_POSTS:
    return Object.assign({}, state, {
      isFetching: true,
      didInvalidate: false
    });
  case RECEIVE_POSTS:
    return Object.assign({}, state, {
      isFetching: false,
      didInvalidate: false,
      items: action.posts,
      lastUpdated: action.receivedAt
    });
  default:
    return state;
  }
}

function postsByReddit(state = { }, action) {
  switch (action.type) {
  case INVALIDATE_REDDIT:
  case RECEIVE_POSTS:
  case REQUEST_POSTS:
    return Object.assign({}, state, {
      [action.reddit]: posts(state[action.reddit], action)
    });
  default:
    return state;
  }
}

const rootReducer = combineReducers({
  postsByReddit,
  selectedReddit
});

export default rootReducer;

Store

configureStore.js

import { createStore, applyMiddleware, combineReducers } from 'redux';
import thunkMiddleware from 'redux-thunk';
import loggerMiddleware from 'redux-logger';
import rootReducer from '../reducers';

const createStoreWithMiddleware = applyMiddleware(
  thunkMiddleware,
  loggerMiddleware
)(createStore);

export default function configureStore(initialState) {
  return createStoreWithMiddleware(rootReducer, initialState);
}

智能组件

containers/Root.js

import React, { Component } from 'react';
import { Provider } from 'react-redux';
import configureStore from '../configureStore';
import AsyncApp from './AsyncApp';

const store = configureStore();

export default class Root extends Component {
  render() {
    return (
      <Provider store={store}>
        {() => <AsyncApp />}
      </Provider>
    );
  }
}

containers/AsyncApp.js

import React, { Component, PropTypes } from 'react';
import { connect } from 'react-redux';
import { selectReddit, fetchPostsIfNeeded, invalidateReddit } from '../actions';
import Picker from '../components/Picker';
import Posts from '../components/Posts';

class AsyncApp extends Component {
  constructor(props) {
    super(props);
    this.handleChange = this.handleChange.bind(this);
    this.handleRefreshClick = this.handleRefreshClick.bind(this);
  }

  componentDidMount() {
    const { dispatch, selectedReddit } = this.props;
    dispatch(fetchPostsIfNeeded(selectedReddit));
  }

  componentWillReceiveProps(nextProps) {
    if (nextProps.selectedReddit !== this.props.selectedReddit) {
      const { dispatch, selectedReddit } = nextProps;
      dispatch(fetchPostsIfNeeded(selectedReddit));
    }
  }

  handleChange(nextReddit) {
    this.props.dispatch(selectReddit(nextReddit));
  }

  handleRefreshClick(e) {
    e.preventDefault();

    const { dispatch, selectedReddit } = this.props;
    dispatch(invalidateReddit(selectedReddit));
    dispatch(fetchPostsIfNeeded(selectedReddit));
  }

  render () {
    const { selectedReddit, posts, isFetching, lastUpdated } = this.props;
    return (
      <div>
        <Picker value={selectedReddit}
                onChange={this.handleChange}
                options={['reactjs', 'frontend']} />
        <p>
          {lastUpdated &&
            <span>
              Last updated at {new Date(lastUpdated).toLocaleTimeString()}.
              {' '}
            </span>
          }
          {!isFetching &&
            <a href='#'
               onClick={this.handleRefreshClick}>
              Refresh
            </a>
          }
        </p>
        {isFetching && posts.length === 0 &&
          <h2>Loading...</h2>
        }
        {!isFetching && posts.length === 0 &&
          <h2>Empty.</h2>
        }
        {posts.length > 0 &&
          <div style={{ opacity: isFetching ? 0.5 : 1 }}>
            <Posts posts={posts} />
          </div>
        }
      </div>
    );
  }
}

AsyncApp.propTypes = {
  selectedReddit: PropTypes.string.isRequired,
  posts: PropTypes.array.isRequired,
  isFetching: PropTypes.bool.isRequired,
  lastUpdated: PropTypes.number,
  dispatch: PropTypes.func.isRequired
};

function mapStateToProps(state) {
  const { selectedReddit, postsByReddit } = state;
  const {
    isFetching,
    lastUpdated,
    items: posts
  } = postsByReddit[selectedReddit] || {
    isFetching: true,
    items: []
  };

  return {
    selectedReddit,
    posts,
    isFetching,
    lastUpdated
  };
}

export default connect(mapStateToProps)(AsyncApp);

笨拙组件

components/Picker.js

import React, { Component, PropTypes } from 'react';

export default class Picker extends Component {
  render () {
    const { value, onChange, options } = this.props;

    return (
      <span>
        <h1>{value}</h1>
        <select onChange={e => onChange(e.target.value)}
                value={value}>
          {options.map(option =>
            <option value={option} key={option}>
              {option}
            </option>)
          }
        </select>
      </span>
    );
  }
}

Picker.propTypes = {
  options: PropTypes.arrayOf(
    PropTypes.string.isRequired
  ).isRequired,
  value: PropTypes.string.isRequired,
  onChange: PropTypes.func.isRequired
};

components/Posts.js

import React, { PropTypes, Component } from 'react';

export default class Posts extends Component {
  render () {
    return (
      <ul>
        {this.props.posts.map((post, i) =>
          <li key={i}>{post.title}</li>
        )}
      </ul>
    );
  }
}

Posts.propTypes = {
  posts: PropTypes.array.isRequired
};
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