Node.js连接在查询完成之前终止

huangapple
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英文:

Node.js Connection terminated before query is finished

问题

新手使用node.js。
我在一个托管有PostgreSQL数据库的Windows服务器上设置了一个Node/express服务器。
我的目标是通过一个HTML表单，将用户在自己计算机上选择的csv文件中的数据插入到数据库中。

以下是用户提交表单后执行的js文件部分：

  1. app.post('/envoi', upload.single("fichiercsv"), async(req, res) => {
  2.     let newClient
  3.     try {
  4.         const { identifiant, motdepasse } = req.body
  5.         const clientConfigModifie = {
  6.             ...clientConfigDefaut,
  7.             user: identifiant,
  8.             password: ''
  9.         }
  10.         newClient = new Client(clientConfigModifie)
  12.         await newClient.connect()
  14.         const rows = []
  15.         const buffer = req.file.buffer
  16.         const readableStreamFromBuffer = new stream.Readable()
  17.         readableStreamFromBuffer.push(req.file.buffer)
  18.         readableStreamFromBuffer.push(null)
  19.         await new Promise((resolve, reject) => {
  20.             fastcsv.parseStream(readableStreamFromBuffer, { headers: false })
  21.                 .on('data', us => {
  22.                     rows.push(us)
  23.                 })
  24.                 .on('end', async() => {
  25.                     rows.shift()
  26.                     const usTotal = rows.map(us => us.join("").split(";"))
  27.                     for (const us of usTotal) {
  28.                         await newClient.query("insert into activite.us (numus, gidgeo) VALUES ($1, $2)", [us[0], us[13]])
  29.                     }
  30.                     resolve()
  31.                 })
  32.                 .on("error", error => console.error(error))
  33.         })
  34.     } catch (e) {
  35.         console.log("erreur lors du traitement", e)
  36.         res.send('<h3>échec de la connexion</h3>')
  37.     } finally {
  38.         try {
  39.             newClient.end()
  40.         } catch (e) {
  41.             console.log(e)
  42.         }
  43.     }
  44. })
  • 如果我省略finally部分，数据将被插入到数据库中，但连接仍在运行...
  • 使用finally部分，只有第一行的us被插入。因此，我收到以下消息：

error: Connection terminated at C:\Apache\balbla\

在这种情况下，似乎newClient.query只运行一次，然后由于某种原因连接被终止但未结束。
我做错了什么？

英文:

Newbie with node.js.
I have set up an Node/express server on a Windows Server hosting a PostgreSQL database.
My goal is to insert in the database the data from a csv file choosen by a user on its own computer, using a HTML form.

Here is the part of the js file executed after the user submits the form:

  1. app.post(&#39;/envoi&#39;, upload.single(&quot;fichiercsv&quot;), async(req, res) =&gt; {
  2. let newClient
  3. try {
  4. const { identifiant, motdepasse } = req.body
  5. const clientConfigModifie = {
  6. ...clientConfigDefaut,
  7. user: identifiant,
  8. password: &#39;&#39;
  9. }
  10. newClient = new Client(clientConfigModifie)
  11. await newClient.connect()
  12. const rows = []
  13. const buffer = req.file.buffer
  14. // console.log(buffer) //ok
  15. const readableStreamFromBuffer = new stream.Readable()
  16. readableStreamFromBuffer.push(req.file.buffer)
  17. readableStreamFromBuffer.push(null)
  18. await new Promise( (resolve, reject) =&gt; {
  19. fastcsv.parseStream(readableStreamFromBuffer, { headers: false })
  20. .on(&#39;data&#39;, us =&gt; {
  21. rows.push(us)	
  22. })
  23. .on(&#39;end&#39;, async() =&gt; { 
  24. rows.shift()
  25. const usTotal = rows.map( us =&gt; us.join(&quot;&quot;).split(&quot;;&quot;))
  26. // console.log(us)
  27. for (const us of usTotal) {
  28. await newClient.query(&quot;insert into activite.us (numus, gidgeo) VALUES ($1, $2)&quot;, [us[0], us[13]])
  29. })
  30. resolve()
  31. })
  32. .on(&quot;error&quot;, error =&gt; console.error(error))
  33. })	
  34. }	
  35. catch(e) {
  36. console.log(&quot;erreur lors du traitement&quot;, e)
  37. res.send(`&lt;h3&gt;&#233;chec de la connexion&lt;/h3&gt;`)
  38. }
  39. finally {
  40. try {
  41. newClient.end()
  42. }
  43. catch(e) { 
  44. console.log(e) 
  45. }
  46. }
  47. })
  • If I omit the finally part, the data are inserted in the database, but the connection is running...
  • With the finally part, only the first row of us is inserted. Thus, I have the message :

error: Connection terminated at C:\Apache\balbla\

In this case, it seems that newClient.query runs one time only then for some reason the connection is terminated but not ended.
What am I doing wrong ?

EDIT : code updated after @I2yscho answer.

答案1

得分: 1

问题是你没有异步处理插入操作。这段代码不是处理这个问题的最佳方式，但它是一个可行的解决方案。我建议你使用某种形式的批量插入来进行一次查询。

  1. .on('end', () => {
  2.     rows.shift();
  3.     const usData = rows.map(us => us.join("").split(";"));
  4.     
  5.     const insertPromises = usData.map(us => {
  6.         return newClient.query("INSERT INTO activite.us (numus, gidgeo) VALUES ($1, $2)", [us[0], us[13]]);
  7.     });
  9.     Promise.all(insertPromises)
  10.         .then(() => {
  11.             resolve();
  12.         })
  13.         .catch(error => {
  14.             reject(error);
  15.         });
  16. })
英文:

Problem is you don't handle insert operations asynchronously. This code is not a best way how to handle this, but it is working solution. I recommend you to use some sort of bulk insert in one query.

  1. .on(&#39;end&#39;, () =&gt; {
  2. rows.shift();
  3. const usData = rows.map(us =&gt; us.join(&quot;&quot;).split(&quot;;&quot;));
  4. const insertPromises = usData.map(us =&gt; {
  5. return newClient.query(&quot;INSERT INTO activite.us (numus, gidgeo) VALUES ($1, $2)&quot;, [us[0], us[13]]);
  6. });
  7. Promise.all(insertPromises)
  8. .then(() =&gt; {
  9. resolve();
  10. })
  11. .catch(error =&gt; {
  12. reject(error);
  13. });
  14. })

huangapple
  • 本文由 发表于 2023年8月9日 18:02:03
  • 转载请务必保留本文链接：https://go.coder-hub.com/76866641.html
  • express
  • node.js
  • postgresql
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