Using node-validator to validate multiple properties at once - node.js

Question

I'm building a Node.js proxy with the intent of handling a single POST request and redirecting the payload to two separate endpoints.
Let's say my JSON payload is:
{
"owner":"0ce856fa-f17f-11e2-9062-9b7910849bf4",
"comment":"My super cool comment!",
"photo":"0928536a-53c4-11e3-ba86-4b026f27c637"
}
I need to validate this payload on the proxy endpoint before I send it off; each of these three properties must exist, and both owner and photo must match the regex below. If they don't pass validation, I need to handle the error(s) and return a message back to the user with an appropriate error code.
I've set up a basic Node.js instance with Express and Validator like so in order to accomplish this:
var url = require('url');
var request = require('request');
var express = require('express');
var check = require('validator').check,
sanitize = require('validator').sanitize;
var app = express();
app.use(express.json());
app.use(express.urlencoded());
app.all('*', function(req, res){
if (req.method == "POST")
{
try {
check(req.body.owner, {
is: "<owner> property of type [uuid] is required"
}).is(/\w{8}(?:-\w{4}){3}-\w{12}?/);
} catch (e) {
console.log(e);
res.json({"result":"failed","message":"Your payload didn't pass validation"});
}
}
});
app.listen(9000, function() {
console.log("Server initialized on port 9000");
});
The problem: this is all fine and dandy and works great for a single validation (in this case owner), but e on catch doesn't contain any details about the property that failed validation -- if I set up multiple checks, I'd have no idea which one failed or why.
How can I set up a series of checks and retrieve the custom message I've configured? It talks about using req.onValidationError in the Validator readme, but that looks to be front-end validation, I'm not clear how (if possible) to integrate that up with the server-side code.

Answer 1

try express-validator which provides errors handling like:
var errors = req.validationErrors();

Answer 2

Update, using express-validator:
Per #shawnzhu's suggestion, I implemented express-validator instead; it took a bit of tweaking to get it working with express+connect 3.0, but given it's handling of node-validator errors, it looks like the best way to go (validating headers notwithstanding).
var express = require('express'),
expressValidator = require('express-validator');
var app = express();
app.use(express.json());
app.use(express.urlencoded());
app.use(expressValidator());
req.checkBody("owner", "<owner> property of type [uuid] is required; " + req.body.owner + " is invalid.").is(uuidRegex);
req.checkBody("photo", "<photo> property of type [uuid] is required; " + req.body.owner + " is invalid.").is(uuidRegex);
req.checkBody("comment", "<comment> property can't be empty").notNull().notEmpty();
req.sanitize("comment").trim();
var errors = req.validationErrors();
if (errors)
{
res.json({"result":"failed","errors":errors});
return;
}
To get it working just with node-validator:
It was the inline message validation that was causing problems:
try {
check(req.body.owner, "<owner> property of type [uuid] is required").is(/\w{8}(?:-\w{4}){3}-\w{12}?/);
check(req.body.photo, "<photo> property of type [uuid] is required").is(/\w{8}(?:-\w{4}){3}-\w{12}?/);
check(req.body.comment, "<comment> property can't be empty").notNull().notEmpty();
} catch (e) {
res.json({"result":"failed","message":e.message});
}
This does the job, and validates each property based on the criteria.