blocks|key|199211|text|您可以将readable和end事件处理程序附加到part流以读取它，而不是管道：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|199212|var+buffers+=+[];
part.on('readable',+function(buffer)+{
++for+(;;)+{
++++let+buffer+=+part.read();
++++if+(!buffer)+{+break;+}
++++buffers.push(buffer);
++}
});
part.on('end',+function()+{
++var+buffer+=+Buffer.concat(buffers);
++...do+your+stuff...

++//+write+to+file:
++fs.writeFile('image/'+%2B+part.filename,+buffer,+function(err)+{
++++//+handle+error,+return+response,+etc...
++});
});|code-block|syntax|javascript|199213|注意:如果您使用data，它会将整个上传内容读取到内存中。|199214|您还可以创建一个自定义的transform+stream来转换传入的数据，但这可能不是一件容易的事情。|199215|entityMap|0|LINK|mutability|MUTABLE|url|http://nodejs.org/api/stream.html#stream_class_stream_transform_1^0|4|8|D|3|P|4|0|0|8|4|0|C|G|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|17|8|@]|D|@$9|18|A|19|1|1A]]|E|$]]|$1|O|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

Instead of piping, you can attach <code>readable</code> and <code>end</code> event handlers to the <code>part</code> stream to read it:
<pre class="lang-js prettyprint-override"><code>var buffers = [];
part.on('readable', function(buffer) {
 for (;;) {
 let buffer = part.read();
 if (!buffer) { break; }
 buffers.push(buffer);
 }
});
part.on('end', function() {
 var buffer = Buffer.concat(buffers);
 ...do your stuff...

 // write to file:
 fs.writeFile('image/' + part.filename, buffer, function(err) {
 // handle error, return response, etc...
 });
});
</code></pre>
Note: If you instead use <code>data</code>, it will read the entire upload into memory.
You could also create a custom <a href="http://nodejs.org/api/stream.html#stream_class_stream_transform_1" rel="nofollow noreferrer">transform stream</a> to transform the incoming data, but that might not be trivial.

blocks|key|199278|text|您可以使用stream-to模块，该模块可以将可读数据流的数据转换为数组或缓冲区：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|199279|var+streamTo+=+require('stream-to');
req.form.on('part',+function+(part)+{
++++streamTo.buffer(part,+function+(err,+buffer)+{
++++++++//+Insert+your+business+logic+here
++++});
});|code-block|syntax|javascript|199280|如果您想更好地了解幕后发生的事情，可以使用Writable+stream自己实现逻辑。作为一个可写的流实现者，您只需要定义一个函数：_write+method，它将在每次向流中写入一些数据时被调用。当输入流完成发送数据时，end+event将被发送:然后我们将使用Buffer.concat+method创建一个缓冲区。|199281|var+stream+=+require('stream');
var+converter+=+new+stream.Writable();

//+We'll+store+all+the+data+inside+this+array
converter.data+=+[];
converter._write+=+function+(chunk)+{
++++converter.data.push(chunk);
};

//+Will+be+emitted+when+the+input+stream+has+ended,+
//+i.e.+no+more+data+will+be+provided
converter.on('finish',+function()+{
++++//+Create+a+buffer+from+all+the+received+chunks
++++var+b+=+Buffer.concat(this.data);

++++//+Insert+your+business+logic+here
});|199282|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/stream-utils/stream-to|1|http://nodejs.org/api/stream.html#stream_class_stream_writable|2|http://nodejs.org/api/stream.html#stream_writable_write_chunk_encoding_callback|3|http://nodejs.org/api/stream.html#stream_event_end|4|http://nodejs.org/api/buffer.html#buffer_class_method_buffer_concat_list_totallength^0|5|9|5|9|0|0|0|L|8|1U|6|33|3|3O|D|L|F|1|1U|D|2|33|9|3|3O|K|4|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@$9|17|A|18|1|19]]|E|$]]|$1|F|3|G|5|H|7|1A|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1B|8|@$9|1C|A|1D|B|C]|$9|1E|A|1F|B|C]|$9|1G|A|1H|B|C]|$9|1I|A|1J|B|C]]|D|@$9|1K|A|1L|1|1M]|$9|1N|A|1O|1|1P]|$9|1Q|A|1R|1|1S]|$9|1T|A|1U|1|1V]]|E|$]]|$1|M|3|N|5|H|7|1W|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|1X|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]|W|$5|R|S|T|E|$U|X]]|Y|$5|R|S|T|E|$U|Z]]|10|$5|R|S|T|E|$U|11]]|12|$5|R|S|T|E|$U|13]]]]

You can use the <a href="https://github.com/stream-utils/stream-to" rel="nofollow noreferrer"><code>stream-to</code></a> module, which can convert a readable stream's data into an array or a buffer:
<pre class="lang-js prettyprint-override"><code>var streamTo = require('stream-to');
req.form.on('part', function (part) {
 streamTo.buffer(part, function (err, buffer) {
 // Insert your business logic here
 });
});
</code></pre>
If you want a better understanding of what's happening behind the scenes, you can implement the logic yourself, using a <a href="http://nodejs.org/api/stream.html#stream_class_stream_writable" rel="nofollow noreferrer"><code>Writable</code> stream</a>. As a writable stream implementor, you only have to define one function: the <a href="http://nodejs.org/api/stream.html#stream_writable_write_chunk_encoding_callback" rel="nofollow noreferrer"><code>_write</code> method</a>, that will be called every time some data is written to the stream. When the input stream is finished emitting data, the <a href="http://nodejs.org/api/stream.html#stream_event_end" rel="nofollow noreferrer"><code>end</code> event</a> will be emitted: we'll then create a buffer using the <a href="http://nodejs.org/api/buffer.html#buffer_class_method_buffer_concat_list_totallength" rel="nofollow noreferrer"><code>Buffer.concat</code> method</a>.
<pre class="lang-js prettyprint-override"><code>var stream = require('stream');
var converter = new stream.Writable();

// We'll store all the data inside this array
converter.data = [];
converter._write = function (chunk) {
 converter.data.push(chunk);
};

// Will be emitted when the input stream has ended, 
// i.e. no more data will be provided
converter.on('finish', function() {
 // Create a buffer from all the received chunks
 var b = Buffer.concat(this.data);

 // Insert your business logic here
});
</code></pre>

How to convert stream into buffer in nodejs? Here is my code to parse a file in post request in express.

<pre><code>app.post('/upload', express.multipart({
defer: true
}), function(req, res) {
req.form.on('part', function(part) {

//Here I want to convert the streaming part into a buffer.
//do something buffer-specific task

 var out = fs.createWriteStream('image/' + part.filename);
 part.pipe(out);
});

req.form.on('close', function() {
 res.send('uploaded!');
 });
});
</code></pre>

Convert stream into buffer?

数据转换

数据流

如何在nodejs中将流转换为buffer？下面是我用express解析post请求中的文件的代码。app.post('/upload', express.multipart({defer: true}), function(req, res) {req.form.on('part', function(part) {...

问是否将流转换为缓冲区？
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