Node.js: how to limit the HTTP request size and up

问题:

I'm using Node.js and express.

I would like to limit the HTTP request size. Let's say, if someone sends me a HTTP request more than 2 MB then I stop the request right away. I looked at the code and I think if I change the core, I can do it. However, is there a way to set a max_request_size or soemthing like that?

It is kind of related to my second question. I'm using express to get an uploaded file from req.files. Is there a way to stop writing the file to the /tmp folder (which is the default upload behavior) as soon as the file size exceeds a certain file size?

回答1:

Just an update (07-2014), as I'm not able to add comments:

As correctly noted above, newer Express versions have deprecated the use of the limit middleware and now provide it as a built-in option for the BodyParser middleware:

   var express    = require('express')
   var bodyParser = require('body-parser')

   var app = express()
   app.use(bodyParser.json({ limit: '5mb' }))

回答2:

Express uses Connect, which has a limit middleware available. You can use this in your Express app by doing something like this:

app.use(express.limit('2mb'));

That, for example, would limit all HTTP requests to 2 MB. Since uploaded files are part of the HTTP request, any file upload larger than 2 MB would be aborted as well.

---

NOTE: This middleware is deprecated and will soon be removed. Discussion on why this is the case is available at: https://github.com/senchalabs/connect/pull/925#issuecomment-26990726

回答3:

Source code of node github :

/* Maximium header size allowed. If the macro is not defined
 * before including this header then the default is used. To
 * change the maximum header size, define the macro in the build
 * environment (e.g. -DHTTP_MAX_HEADER_SIZE=<value>). To remove
 * the effective limit on the size of the header, define the macro
 * to a very large number (e.g. -DHTTP_MAX_HEADER_SIZE=0x7fffffff)
 */
#ifndef HTTP_MAX_HEADER_SIZE
# define HTTP_MAX_HEADER_SIZE (80*1024)
#endif 

So, you need to rebuild node from source to surpass the limit of 80*1024

You can use this with Express 4 to limit request body size/Upload file size, instead of express.json() and express.urlencoded(), you must require the body-parser module and use its json() and urlencoded() methods, if the extended option is not explicitly defined for bodyParser.urlencoded(), it will throw a warning (body-parser deprecated undefined extended: provide extended option).

var bodyParser = require('body-parser');
app.use(bodyParser.json({limit: '50mb'}));
app.use(bodyParser.urlencoded({limit: '50mb', extended: true}));

回答4:

Use raw-body. Most middleware (like limit) is no longer bundled with Express and must be installed separately. Here's an example.

var getRawBody = require('raw-body')
app.use(function (req, res, next) {
      getRawBody(
        stream = req,
        options = {
          length: req.headers['content-length'],
          limit: '100mb',
        },
        callback = function (err, reslt) {
          if (err) {
            return next(err)
          }
          next();
          console.log(req)
        })
    })

• Remember to add the router after the app.use

Express no longer allows you to explicitly set the limit using the traditional bundled middleware as show below.

app.use(express.limit('4M'));

回答5:

Answer for Question 1:

To limit the HTTP request size and upload file size we need to set the body-parser limit.

app.use(bodyParser.urlencoded({limit: '50mb',extended: true}));
app.use(bodyParser.json({limit: '50mb'}));

bodyParser.urlencoded

The files from the front end comes as urlencoded bodies.

Returns middleware that only parses urlencoded bodies. This parser accepts only UTF-8 encoding of the body and supports automatic inflation of gzip and deflate encodings.

A new body object containing the parsed data is populated on the request object after the middleware (i.e. req.body). This object will contain key-value pairs, where the value can be a string or array (when extended is false), or any type (when extended is true).

bodyParser.json

Returns middleware that only parses json. This parser accepts any Unicode encoding of the body and supports automatic inflation of gzip and deflate encodings.

A new body object containing the parsed data is populated on the request object after the middleware (i.e. req.body).

Note: By default the input limit for body parser is 100kb

Answer for Question 2:

To change the default upload directory we can use the following.

app.set('uploadDir', './files');  // Sets the upload Directory to files folder in your project.

Other Implementation

While including the bodyParser into the app we can mention the upload directory.

app.use(express.bodyParser({uploadDir:'./files', keepExtensions: true}));

Reference:

• https://github.com/expressjs/body-parser#limit
• https://github.com/expressjs/body-parser#bodyparserjsonoptions
• https://github.com/expressjs/body-parser#bodyparserurlencodedoptions

Issues: https://github.com/expressjs/express/issues/1684

Hope this helps!

回答6:

For an updated solution that isn't deprecated, you can add the limit like so, in your app.js file:

app.use(express.json({limit: '2mb'}));
app.use(express.urlencoded({limit: '2mb', extended: false}));

You can also do it like this:

app.use(express.json({limit: 2000000}));
app.use(express.urlencoded({limit: 2000000, extended: false}));

回答7:

var methodOverride = require('method-override');
app.use(bodyParser.urlencoded({
        extended: true, limit: '50mb'
    }));
app.use(bodyParser.json({limit: '50mb'}));
app.use(methodOverride());