如何在reactjs中将文件路径转换为URL

Question

我正在尝试修改代码以从URL加载Json文件，而不是从本地文件使用。 谁能解释一下如何解决这个问题

const TAXONOMY_DATA = require(../../assets/chord.json);

//for filters**
class AddRemoveSelection extends Component {
    constructor(props) {
        super(props);

        this.state = {
            selectedOptions: []
        }
    }

    handleDeselect = (deselectedOptions) => {
        var selectedOptions = this.state.selectedOptions.slice()
        deselectedOptions.forEach(option => {
            selectedOptions.splice(selectedOptions.indexOf(option), 1)
        })
        this.setState({ selectedOptions })
        this.props.onChange(selectedOptions)
    }

    handleSelect = (selectedOptions) => {
        selectedOptions.sort((a, b) => a.id - b.id)
        this.setState({ selectedOptions })
        this.props.onChange(selectedOptions)
    }

    componentWillReceiveProps(nextProps) {
        if (nextProps.options !== this.props.options) {
            this.setState({ selectedOptions: nextProps.options });
        }
    }

    render() {
        const { selectedOptions } = this.state
        const { options, type } = this.props

        return <div className="row mt-20">
            <div className="col-sm-6">
                <FilteredMultiSelect
                    placeholder={`Select ${type}`}
                    buttonText="Add"
                    classNames={{
                        filter: 'form-control',
                        select: 'form-control',
                        button: 'btn btn btn-block btn-default',
                        buttonActive: 'btn btn btn-block btn-primary',
                    }}
                    onChange={this.handleSelect}
                    options={options}
                    selectedOptions={selectedOptions}
                    textProp="name"
                    valueProp="id"
                />
            </div>
            <div className="col-sm-6">
                <FilteredMultiSelect
                    placeholder={`Visible ${type}`}
                    buttonText="Delete"
                    classNames={{
                        filter: 'form-control',
                        select: 'form-control',
                        button: 'btn btn btn-block btn-default',
                        buttonActive: 'btn btn btn-block btn-danger'
                    }}
                    onChange={this.handleDeselect}
                    options={selectedOptions}
                    textProp="name"
                    valueProp="id"
                />
            </div>
        </div>
    }
}


export default class ChordFinal extends Component {
    constructor(props) {
        super(props);
        this.state = {
            master: {},
            filterKeyword: {},
            filterTaxonomy: {},
            tooltip: {},
            pFormat: d3.format(".1%"),
            qFormat: d3.format(",.0f"),

            rankList: [],
            categoryList: [],
            selectedRank: "",
            selectedCategory: "",

            keywordsOptions: [],
            selectedKeywordsOptions: [],
            taxonomyOptions: [],
            selectedTaxonomyOptions: [],
        };

        this.importJSON = this.importJSON.bind(this);
        this.addFilter = this.addFilter.bind(this);
        this.updateChart = this.updateChart.bind(this);
        this.updateTooltip = this.updateTooltip.bind(this);
        this.reset = this.reset.bind(this);
        this.setFilters = this.setFilters.bind(this);
    }

    toggleVisibility = () => this.setState({ visible: !this.state.visible })

    updateTooltip = (data) => {
        console.log(data);

        this.setState({
            tooltip: data
        });
    };



    addFilter = (name) => {
        let filters = this.state.filters;
        filters[name] = {
            name: name,
            hide: true
        };
        this.setState({
            hasFilters: true,
            filters: filters
        });
        this.update()
    };

    // 1 - parse the data to get the list of ranks and categories
    importJSON() {

        // temporary dictionaries
        const ranks = {}
        const categories = {}
        const master = {}
        const rankList = []
        const categoryList = []

        TAXONOMY_DATA.fulldata.forEach(d => {
            const rank = d.taxonomyRank;
            const keyword = d.keywordCategory;

            ranks[rank] = true;
            categories[keyword] = true;
            if (!master[rank]) {
                master[rank] = {}
            }
            if (!master[rank][keyword]) {
                master[rank][keyword] = []
            }
            master[rank][keyword].push(d);
        })

        // add ranks/categories to list
        for (let key in ranks) {
            if (ranks.hasOwnProperty(key)) {
                rankList.push(key);
            }
        }

        for (let key in categories) {
            if (categories.hasOwnProperty(key)) {
                categoryList.push(key);
            }
        }
        console.log('rankList', rankList)
        console.log('categoryList', categoryList)
        console.log('master', master)

        this.setState({
            rankList,
            categoryList,
            master,

            selectedRank: "superfamily",
            selectedCategory: "Biological process",
        }, () => {
            this.updateList()
        });
    }

    // create taxonomy/keyword list
    updateList() {
        // temporary dictionary
        const keywords = {}
        const taxonomies = {}
        const { master, selectedRank, selectedCategory } = this.state
        console.log(`master[${selectedRank}][${selectedCategory}]`)

        if (master && master[selectedRank] && master[selectedRank][selectedCategory]) {
            console.log(`master[${selectedRank}][${selectedCategory}]`, master[selectedRank][selectedCategory])
            master[selectedRank][selectedCategory].forEach(d => {
                keywords[d.keywordId] = d.keywordName;
                taxonomies[d.taxId] = d.taxonomyName;
            })

            const keywordsOptions = [];
            const taxonomyOptions = [];

            // creates keyword list
            for (let key in keywords) {
                if (keywords.hasOwnProperty(key)) {
                    keywordsOptions.push({ id: key, name: keywords[key] });
                }
            }

            // creates taxonomy list
            for (let key in taxonomies) {
                if (taxonomies.hasOwnProperty(key)) {
                    taxonomyOptions.push({ id: key, name: taxonomies[key] });
                }
            }

            const selectedKeywordsOptions = keywordsOptions.slice();
            const selectedTaxonomyOptions = taxonomyOptions.slice();

            this.setState({
                keywordsOptions,
                selectedKeywordsOptions,
                taxonomyOptions,
                selectedTaxonomyOptions,

                filterKeyword: keywords,
                filterTaxonomy: taxonomies,
            }, () => {
                this.updateChart();
            });
        }
    }

    updateChart() {
        const { master, selectedRank, selectedCategory, filterKeyword, filterTaxonomy } = this.state;
        const data = master[selectedRank][selectedCategory];
        if (data) {
            this.child.drawChords(data.filter(d => (filterKeyword[d.keywordId] && filterTaxonomy[d.taxId])));
        }
    };

    setFilters(item, input) {
        let state = this.state;
        state.filters[item.name] = {
            name: item.name,
            hide: input.target.checked
        }
        this.setState({
            filters: state.filters
        });
        this.update(state);
    }

    reset() {
        let state = this.state;
        if (Object.keys(state.filters).length > 0 && state.hasFilters {
            state.filters = {};
            state.hasFilters = false;
            this.setState({
                filters: {},
                hasFilters: false
            });
            this.updateChart();
        }
    }

    componentDidMount() {
        this.setState({ isComponentMount: true });

        this.importJSON();
    }

    render =() => {
        let state = this.state;
        const { visible, rankList, categoryList, selectedRank, selectedCategory } = this.state

        return <div>
            <Sidebar.Pushable as={Segment}>
              <Button onClick={this.toggleVisibility} icon className="navbar-toggle">
                <Icon name="align justify"/>
              </Button>
              <Sidebar as={Menu} animation="overlay" width="very wide" direction="right" visible={visible} icon="labeled" vertical inverted>
                <Icon className="close" size="large" onClick={this.toggleVisibility} />
                <div className="row mt-50" />
                <div className="row mt-20">
                  <div className="col-sm-6">
                    <Dropdown placeholder="Select Rank" selection value={selectedRank} options={rankList.map(
                        item => ({ key: item, text: item, value: item })
                      )} onChange={(e, data) => {
                        this.setState(
                          { selectedRank: data.value },
                          () => {
                            this.updateList();
                          }
                        );
                      }} />
                  </div>
                  <div className="col-sm-6">
                    <Dropdown placeholder="Select Category" selection value={selectedCategory} options={categoryList.map(
                        item => ({ key: item, text: item, value: item })
                      )} onChange={(e, data) => {
                        this.setState(
                          { selectedCategory: data.value },
                          () => {
                            this.updateList();
                          }
                        );
                      }} />
                  </div>
                </div>
                <AddRemoveSelection type="Taxonomy" options={this.state.taxonomyOptions} onChange={selectedTaxonomyOptions
{
                    this.setState({ selectedTaxonomyOptions });
                  }} />
                <br />
                <AddRemoveSelection type="Keywords" options={this.state.keywordsOptions} onChange={selectedKeywordsOptions
{
                    this.setState({ selectedKeywordsOptions });
                  }} />
                <div className="row mt-20">
                  <div className="col-sm-12 text-left">
                    <button className="btn btn-primary" id="submit" onClick={this.toggleVisibility}>
                      Submit
                    </button>
                    <button className="btn btn-danger"  id="reset" onClick={this.reset}>
                      Reset
                    </button>
                  </div>
                </div>
              </Sidebar>
              <Sidebar.Pusher>
                <Segment basic>
                  <div className="row" style={{ position: "relative" }}>
                    <div className="large-8 small-12" role="content">
                      <article style={{ width: 800, height: 800 }} id="chord">
                        {state.isComponentMount ? 
                            <Chord updateTooltip={this.updateTooltip} addFilter={this.addFilter} onRef={ref => (this.child = ref)} filters={state.filters} />
                        : null}
                      </article>
                    </div>
                    <fieldset id="tooltip" placement="top" className="row">
                      <div className="small-6 small-12 ">
                        <h6>
                          Taxonomy Name: {state.tooltip.tname} <br /> Keyword Name: {state.tooltip.kname} <br /> Taxonomy ID: {state.tooltip.tid} <br /> Keyword Visibility: {state.tooltip.kwVizState} <br /> Taxonomy Visibility: {state.tooltip.taxVizState} <br /> Keyword ID: {state.tooltip.kid} <br /> Spect Count: {state.tooltip.tvalue}{" "}
                        </h6>
                      </div>
                    </fieldset>
                  </div>
                </Segment>
              </Sidebar.Pusher>
            </Sidebar.Pushable>
          </div>;
    }
}




    // 1 - parse the data to get the list of ranks and categories
    importJSON() {

        // temporary dictionaries
        const ranks = {}
        const categories = {}

        const master = {}
        const rankList = []
        const categoryList = []


          //to be placed for fullDataChord API fetch once it'S available
        //    d3.json('https://bitbucket.org/rohitkalva/viz/raw/11e7059eceaf571b12bf97d348cc157e5bf11fa3/fulldata.json')


        TAXONOMY_DATA.fulldata.forEach(d => {
            const rank = d.taxonomyRank;
            const keyword = d.keywordCategory;

            ranks[rank] = true;
            categories[keyword] = true;
            if (!master[rank]) {
                master[rank] = {}
            }
            if (!master[rank][keyword]) {
                master[rank][keyword] = []
            }
            master[rank][keyword].push(d);
        })


        // add ranks/categories to list
        for (let key in ranks) {
            if (ranks.hasOwnProperty(key)) {
                rankList.push(key);
            }
        }

        for (let key in categories) {
            if (categories.hasOwnProperty(key)) {
                categoryList.push(key);
            }
        }
        console.log('rankList', rankList)
        console.log('categoryList', categoryList)
        console.log('master', master)

        this.setState({
            rankList,
            categoryList,
            master,
            // selectedRank: rankList[0],
            // selectedCategory: categoryList[0],
            selectedRank: "superfamily",
            selectedCategory: "Biological process",
        }, () => {
            this.updateList()
        });
    }

    // create taxonomy/keyword list
    updateList() {
        // temporary dictionary
        const keywords = {}
        const taxonomies = {}
        const { master, selectedRank, selectedCategory } = this.state
        console.log(`master[${selectedRank}][${selectedCategory}]`)

        if (master && master[selectedRank] && master[selectedRank][selectedCategory]) {
            console.log(`master[${selectedRank}][${selectedCategory}]`, master[selectedRank][selectedCategory])
            master[selectedRank][selectedCategory].forEach(d => {
                keywords[d.keywordId] = d.keywordName;
                taxonomies[d.taxId] = d.taxonomyName;
            })

            const keywordsOptions = [];
            const taxonomyOptions = [];

            // creates keyword list
            for (let key in keywords) {
                if (keywords.hasOwnProperty(key)) {
                    keywordsOptions.push({ id: key, name: keywords[key] });
                }
            }

            // creates taxonomy list
            for (let key in taxonomies) {
                if (taxonomies.hasOwnProperty(key)) {
                    taxonomyOptions.push({ id: key, name: taxonomies[key] });
                }
            }

            const selectedKeywordsOptions = keywordsOptions.slice();
            const selectedTaxonomyOptions = taxonomyOptions.slice();

            this.setState({
                keywordsOptions,
                selectedKeywordsOptions,
                taxonomyOptions,
                selectedTaxonomyOptions,

                filterKeyword: keywords,
                filterTaxonomy: taxonomies,
            }, () => {
                this.updateChart();
            });
        }

    }




    updateChart() {
        const { master, selectedRank, selectedCategory, filterKeyword, filterTaxonomy } = this.state;
        const data = master[selectedRank][selectedCategory];
        if (data) {
            this.child.drawChords(data.filter(d => (filterKeyword[d.keywordId] && filterTaxonomy[d.taxId])));
        }
    };

    setFilters(item, input) {
        let state = this.state;
        state.filters[item.name] = {
            name: item.name,
            hide: input.target.checked
        }
        this.setState({
            filters: state.filters
        });
        this.update(state);
    }

    reset() {
        let state = this.state;
        if (Object.keys(state.filters).length > 0 && state.hasFilters) {
            state.filters = {};
            state.hasFilters = false;
            this.setState({
                filters: {},
                hasFilters: false
            });
            this.updateChart();
        }
    }

    componentDidMount() {
        this.setState({ isComponentMount: true });

        this.importJSON();
    }

Answer 1

React并不介意您如何进行API（URL）调用。 您可以为该任务选择喜欢的任何一种AJAX库。 最简单的方法是这样。

  importJSON() {

        const ranks = {}
        const categories = {}
        const master = {}
        const rankList = []
        const categoryList = []

        var request = new XMLHttpRequest();
        request.open('GET', '/my/url', true);
        request.setRequestHeader('Content-Type', 'application/json');
        request.onreadystatechange = function() {
        if (this.readyState == 4 && this.status == 200) {

          this.state({
                    TAXONOMY_DATA: xhttp.responseText
                }, ()=> {
                    this.state.TAXONOMY_DATA.fulldata.forEach(d => {
                    const rank = d.taxonomyRank;
                    const keyword = d.keywordCategory;

                    ranks[rank] = true;
                    categories[keyword] = true;
                    if (!master[rank]) {
                        master[rank] = {}
                    }
                    if (!master[rank][keyword]) {
                        master[rank][keyword] = []
                    }
                    master[rank][keyword].push(d);
                });
            });

        }
    };
        request.send();
 // add ranks/categories to list
        for (let key in ranks) {
            if (ranks.hasOwnProperty(key)) {
                rankList.push(key);
            }
        }

        for (let key in categories) {
            if (categories.hasOwnProperty(key)) {
                categoryList.push(key);
            }
        }
        console.log('rankList', rankList)
        console.log('categoryList', categoryList)
        console.log('master', master)

        this.setState({
            rankList,
            categoryList,
            master,

            selectedRank: "superfamily",
            selectedCategory: "Biological process",
        }, () => {
            this.updateList()
        });
    }

Answer 2

而不是一开始就require

const TAXONOMY_DATA = require(../../assets/chord.json);

利用提取API ：

constructor(props) {
    super(props);

    this.state = {
        selectedOptions: [],
        TAXONOMY_DATA: null 
    }
}


importJSON() {

    const ranks = {}
    const categories = {}
    const master = {}
    const rankList = []
    const categoryList = []

    fetch("https://.../chord.json")
        .then( (response) => {
            return response.json() 
        })   
        .then( (json) => {
            this.setState({
                TAXONOMY_DATA: json
            }, ()=> {
                this.state.TAXONOMY_DATA.fulldata.forEach(d => {
                    const rank = d.taxonomyRank;
                    const keyword = d.keywordCategory;

                    ranks[rank] = true;
                    categories[keyword] = true;
                    if (!master[rank]) {
                        master[rank] = {}
                    }
                    if (!master[rank][keyword]) {
                        master[rank][keyword] = []
                    }
                    master[rank][keyword].push(d);

                     ...

                    this.setState({
                        rankList,
                        categoryList,
                        master,
                        selectedRank: "superfamily",
                        selectedCategory: "Biological process",
                    }, () => {
                        this.updateList()
                    });
            });
        });

}

并且因为您在componentDidMount()部署了importJSON ，这意味着您在所有元素都呈现一次之后就请求数据。 这会导致问题，因为您在importJSON有很多值分配，并且在第一次渲染时没有这些值，您需要确保this.state.TAXONOMY_DATA已结算，然后通过

render =() => {
    ...
    if(this.state.TAXONOMY_DATA) {
        const { visible, rankList, categoryList, selectedRank, selectedCategory } = this.state`
        return (<div>...</div>)
    } else {
        return null;
    }
    ...
}