Question

我有一个很奇怪的问题。我有一个后端api，可以将json数据导入到我的mongodb中。

在屏幕上，我有一个上传按钮来上传文件，为此我使用了react-dropzone。例如，以为我有一个像“ db.json”的文件，并且在这个文件中有一个如下的json

{
"datapointtypes":[
    {"id":"Wall plug","features":[{"providesRequires":"provides","id":"Binary switch"},{"providesRequires":"requires","id":"Binary sensor","min":"1","max":"2"}],"parameters":[{"id":"Communication type","type":"Communication type"}],"functions":[{"id":"Electricity"},{"id":"Switch"}]},
    {"id":"Door sensor","features":[{"providesRequires":"provides","id":"Binary sensor"}],"parameters":[{"id":"Communication type","type":"Communication type"}],"functions":[{"id":"Door"},{"id":"Sensor"}]}
],
"datatypes":[
    {"id":"Communication type","type":"enum","values":[{"id":"Zwave"},{"id":"Zigbee"}]},
    {"id":"Zigbee network address","type":"decimal","min":1,"max":65336,"res":1},
    {"id":"Serial port","type":"string"}
],
"features":[
    {"id":"Zwave receiver","exposedtype":"Zwave command","functions":[{"id":"Communication"}]},
    {"id":"Zigbee receiver","exposedtype":"Zigbee command","functions":[{"id":"Communication"}]},
    {"id":"Binary switch","exposedtype":"On off state","functions":[{"id":"Actuator"}]},
    {"id":"Binary sensor","exposedtype":"On off state","functions":[{"id":"Sensor"}]}
],
"servicetypes":[
    {"id":"Room controller","datapointtype":"Room controller","DelayActive":false,"DelayValue":""},
    {"id":"Xiaomi door sensor","datapointtype":"Door sensor","parameters":[{"id":"Zigbee network address","type":"Zigbee network address"},{"id":"Zigbee node id","type":"Zigbee node id"}],"parametervalues":[{"id":"Communication type","value":"Zigbee"}]}
],
"systems":[
    {"id":"system 2","services":[{"serviceType":"Room controller","id":"servis 1"}],"serviceRelations":[{"serviceName":"servis 1","featureName":"Binary sensor"}],"parametervalues":[{"id":"Delay","paramName":"Delay","serviceType":"Room controller","value":"binary"}]},
    {"id":"system 3","services":[{"serviceType":"Room controller","id":"servis 1"}],"serviceRelations":[{"serviceName":"servis 1","featureName":"Binary sensor"}],"katid":"7"}
]
}

问题是这样的。如果浏览器控制台已打开，则我的代码成功运行，并且可以将json数据导入到mongodb中。但是，如果关闭浏览器控制台，则会出现“ SyntaxError：JSON输入意外终止” 错误。

这是我在导入按钮上使用的功能

class FileUpload extends Component {
state = {
    warning: ""
}

uploadFile = (files, rejectedFiles) => {
    files.forEach(file => {
        const reader = new FileReader();

        reader.readAsBinaryString(file);
        let fileContent = reader.result;

        axios.post('http://localhost:3001/backendUrl', JSON.parse(fileContent),
            {
                headers: { 
                    "Content-Type": "application/json" 
                }
            })
            .then(response => {
                this.setState({warning: "Succeed"})
            })
            .catch(err => {
                console.log(err)
            });
    });
}

render() {
    return (
        <div>
            <Dropzone className="ignore" onDrop={this.uploadFile}>{this.props.children}
            </Dropzone>
            {this.state.warning ? <label style={{color: 'red'}}>{this.state.warning}</label> : null}
        </div>
    )
}

}

我做错了什么或者是什么原因导致的？你能帮我吗？

谢谢

Answer 1

FileReader异步读取文件，因此您必须使用回调来访问结果
如果JSON中有非ascii字符，我会使用readAsText而不是readAsBinaryString 最后，JSON.parse将JSON字符串转换为对象（或任何可能的类型）。 fileContent已经是JSON，因此请保持不变。

    const reader = new FileReader();
    reader.onlooad = (e) => {
        let fileContent = this.result;

        axios.post('http://localhost:3001/backendUrl', fileContent,
        {
            headers: { 
                "Content-Type": "application/json" 
            }
        })
        .then(response => {
            this.setState({warning: "Succeed"})
        })
        .catch(err => {
            console.log(err)
        });
    }
    reader.readAsText(file);

使用axios将json数据发布到我的数据库（使用我的后端api）

1 个答案: