如何直接从内存中索引 JSON 文档

Question

我正在尝试为 JSON 文档编制索引，但它根本不起作用；到目前为止，我已经尝试了https://developer.ibm.com/answers/questions/361808/adding-a-json-document-to-a-discovery-collection-u/ 中发布的解决方案，但它根本不起作用；

如果我尝试：

    discovery.addDocument({
        environment_id: config.watson.environment_id,
        collection_id: config.watson.collection_id,
        file: JSON.stringify({
            "ocorrencia_id": 9001
        })
    }, (error, data) => {
        if (error) {
            console.error(error);
            return;
        }

        console.log(data);
    });

它返回给我这个错误：

    The Media Type [text/plain] of the input document is not supported. Auto correction was attempted, but the auto detected media type [text/plain] is also not supported. Supported Media Types are: application/json, application/msword, application/vnd.openxmlformats-officedocument.wordprocessingml.document, application/pdf, text/html, application/xhtml+xml .

另一方面，如果我尝试：

    discovery.addDocument({
        environment_id: config.watson.environment_id,
        collection_id: config.watson.collection_id,
        file: JSON.parse(JSON.stringify({
            "ocorrencia_id": 9001
        }))
    }, (error, data) => {
        if (error) {
            console.error(error);
            return;
        }

        console.log(data);
    });

我收到此错误：

TypeError: source.on is not a function
    at Function.DelayedStream.create (C:\Temp\teste-watson\watson-orchestrator\node_modules\delayed-stream\lib\delayed_stream.js:33:10)
    at FormData.CombinedStream.append (C:\Temp\teste-watson\watson-orchestrator\node_modules\combined-stream\lib\combined_stream.js:43:37)
    at FormData.append (C:\Temp\teste-watson\watson-orchestrator\node_modules\form-data\lib\form_data.js:68:3)
    at appendFormValue (C:\Temp\teste-watson\watson-orchestrator\node_modules\request\request.js:324:21)
    at Request.init (C:\Temp\teste-watson\watson-orchestrator\node_modules\request\request.js:337:11)
    at new Request (C:\Temp\teste-watson\watson-orchestrator\node_modules\request\request.js:130:8)
    at request (C:\Temp\teste-watson\watson-orchestrator\node_modules\request\index.js:54:10)
    at createRequest (C:\Temp\teste-watson\watson-orchestrator\node_modules\watson-developer-cloud\lib\requestwrapper.js:177:10)
    at DiscoveryV1.addDocument (C:\Temp\teste-watson\watson-orchestrator\node_modules\watson-developer-cloud\discovery\v1.js:516:10)
    at client.query.then.res (C:\Temp\teste-watson\watson-orchestrator\populate\populate.js:36:13)
    at process._tickCallback (internal/process/next_tick.js:109:7)

同样，通过保存到临时文件，然后使用它：

    const tempy = require('tempy');
    const f = tempy.file({extension: 'json'});
    fs.writeFileSync(f, JSON.stringify({
            "ocorrencia_id": 9001
    }));

    discovery.addDocument({
        environment_id: config.watson.environment_id,
        collection_id: config.watson.collection_id,
        file: fs.readFileSync(f)
    }, (error, data) => {
        if (error) {
            console.error(error);
            return;
        }

        console.log(data);
    });

然后发生这种情况：

The Media Type [application/octet-stream] of the input document is not supported. Auto correction was attempted, but the auto detected media type [text/plain] is also not supported. Supported Media Types are: application/json, application/msword, application/vnd.openxmlformats-officedocument.wordprocessingml.document, application/pdf, text/html, application/xhtml+xml .

考虑到其他帖子建议使用 JSON.parse()，似乎 API 接受了一个 JS 对象，但没有一个示例，而且到目前为止我尝试过的任何方法似乎都不起作用。好像是bug？

更新：通过保存到一个临时文件，然后使用createDataStream()，而不是readFileSync()，它可以工作，但它仍然是一个很大的麻烦，必须通过磁盘获取已经在内存中的信息。

我也试过create a in-memory stream from a Readable，但也失败了：

    var Readable = require('stream').Readable;
    var s = new Readable();
    s._read = function noop() {}; // redundant? see update below
    s.push(JSON.stringify({
            "ocorrencia_id": 9001
    }));        
    s.push(null);

    discovery.addDocument({
        environment_id: config.watson.environment_id,
        collection_id: config.watson.collection_id,
        file: s
    }, (error, data) => {
        if (error) {
            console.error(error);
            return;
        }

        console.log(data);
    });

这个失败了：

Error: Unexpected end of multipart data
    at Request._callback (C:\Temp\teste-watson\watson-orchestrator\node_modules\watson-developer-cloud\lib\requestwrapper.js:88:15)
    at Request.self.callback (C:\Temp\teste-watson\watson-orchestrator\node_modules\request\request.js:188:22)
    at emitTwo (events.js:106:13)
    at Request.emit (events.js:191:7)
    at Request.<anonymous> (C:\Temp\teste-watson\watson-orchestrator\node_modules\request\request.js:1171:10)
    at emitOne (events.js:96:13)
    at Request.emit (events.js:188:7)
    at Gunzip.<anonymous> (C:\Temp\teste-watson\watson-orchestrator\node_modules\request\request.js:1091:12)
    at Gunzip.g (events.js:292:16)
    at emitNone (events.js:91:20)
    at Gunzip.emit (events.js:185:7)
    at endReadableNT (_stream_readable.js:974:12)
    at _combinedTickCallback (internal/process/next_tick.js:80:11)
    at process._tickCallback (internal/process/next_tick.js:104:9) code: 500, error: 'Unexpected end of multipart data'

Answer 1

该服务检查文件名，然后检查内容以确定类型，但似乎无法正确识别 JSON 内容 - 它只看到文本。只要文件名以.json 结尾（它不关心contentType），另一个答案就可以了。

但是，我们在 node.js SDK 中添加了 .addJsonDocument() 和 .updateJsonDocument() 方法以使其更加简单：

discovery.addJsonDocument({
    environment_id: config.watson.environment_id,
    collection_id: config.watson.collection_id,

    // note: no JSON.stringify needed with addJsonDocument()
    file: { 
        "ocorrencia_id": 9001
    }
}, (error, data) => {
    if (error) {
        console.error(error);
        return;
    }

    console.log(data);
});

Answer 2

您遇到的问题是因为缺少内容类型（默认为 text/plain）。当您提供要作为字符串上传的文档时，您需要提供内容类型和文件名。在这种情况下，您可以尝试将以下内容用于您的目的

discovery.addDocument({
  //other required parameters 
  file: {
    value: JSON.stringify({ "ocorrencia_id": 9001 }),
    options: {
      filename: "some_file_name",
      contentType: "application/json; charset=utf-8"
    }
  } 
}, callbackFn)