Reading node js doc. They seems to be conservative in the default limit values for http body size and parameters quantity:
I've found you can extend it and this seems to be a proved solution:
var bodyParser = require('body-parser');
app.use(bodyParser.urlencoded({ parameterLimit: 100000, limit: '50mb', extended: true }));
However, two questions remain:
- Why the default values are so conservative?
- Why expanding the limit to 50mb is a good idea?
I know the answers depend on the application the solution is applied, but I would appreciate a more general approach oriented answer to understand better the problem.
2 Answers
The answer seems to be the encoding of the HTTP payload.
The Express.js docs () say that bodyParser.urlencoded parses x-www-form-urlencoded data.
MDN () basically says that x-www-form-urlencoded data is key/value pairs and (I’m reading in between the lines here) not suitable for large amounts of data transmission (use multipart/form-data encoding to send large amounts of data):
x-www-form-urlencoded: the values are encoded in key-value tuples separated by '&', with a '=' between the key and the value. Non-alphanumeric characters are percent encoded: this is the reason why this type is not suitable to use with binary data (use multipart/form-data instead)
bodyParser seems to limit the data as a safety measure to help keep us from running in to transmission errors / issues. At least, that's how I read it.
I'm struggling to think of a legitimate use case where the API would need to accept more than 100 parameters in a single request. Reviewing The Open Web Application Security Project (OWASP) guidelines (CHEATSHEET HERE), the default limit values set by ExpressJS seem aligned and responsible. I wouldn't change them.
If you're going down a road where you think these limits may inhibit you from providing the functionality you need, I would strongly consider rethinking your strategy as this will likely open you to unnecessarily security vulnerabilities. For example, you could make multiple smaller requests etc.
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