# Rexml exceptions **URL:** \ **Category:** Ruby\ **Created:** [September 30, 2008, 4:58am UTC](https://www.ruby-forum.com/t/rexml-exceptions/149811 "2008-09-30T04:58:22Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\ **Post date:** [September 30, 2008, 4:58am UTC](https://www.ruby-forum.com/t/rexml-exceptions/149811/1 "2008-09-30T04:58:22Z")
Is there any way to get any useful data out of REXML::ParseException when you’re working on a String? It never sets @position or @line or anything. I need to figure out exactly where the error-causing tag starts, and save it. Any ideas? – rakaur ---
**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\ **Post date:** [September 30, 2008, 4:01pm UTC](https://www.ruby-forum.com/t/rexml-exceptions/149811/2 "2008-09-30T16:01:47Z")
On Sep 29, 10:56 pm, Eric W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Is there any way to get any useful data out of REXML::ParseException > when you’re working on a String? It never sets @position or @line or > anything. I need to figure out exactly where the error-causing tag > starts, and save it. > > Any ideas? Out of curiosity, I tried libxml. It has nice error messages: foo.xml:3: parser error : Opening and ending tag mismatch: title line 3 and txitle Foo ^ but they go to stdout. You can capture them by registering an error handler. Sample code: parser = XML::Parser.new parser.filename = “foo.xml” msgs = [] XML::Parser.register\_error\_handler lambda { |msg| msgs \<\< msg } begin parser.parse rescue Exception =\> e puts “Error: #{msgs}” end – Mark. ---
**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\ **Post date:** [September 30, 2008, 6:19pm UTC](https://www.ruby-forum.com/t/rexml-exceptions/149811/3 "2008-09-30T18:19:29Z")
On Tue, Sep 30, 2008 at 9:59 AM, Mark T. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > end > Interesting. I was thinking about doing libxml anyway. I do not like > REXML. Thanks. > – Mark. – rakaur ---
**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\ **Post date:** [September 30, 2008, 7:41pm UTC](https://www.ruby-forum.com/t/rexml-exceptions/149811/4 "2008-09-30T19:41:47Z")
On Sep 30, 12:46 pm, Eric W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Actually, this isn’t working for me. I’m using the SAX parser, and it > just calls Listener#on\_parser\_error with a string. Not helping me. Why would you want to do that? You already have the XML as a string. The only reason to put up with the awful interface and extra complexity of SAX would be if your file doesn’t fit into memory. And I don’t think the SAX interface to libxml is as complete/robust yet as the DOM interface. Go with the DOM interface. With libxml it’s plenty fast. – Mark. ---
**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\ **Post date:** [September 30, 2008, 8:10pm UTC](https://www.ruby-forum.com/t/rexml-exceptions/149811/5 "2008-09-30T20:10:31Z")
My situation requires SAX, unfortunately. I need to parse and react to each tag as in comes in. If there’s a broken one, all tags up to the broken one must be processed, and the broken one must be stored. I cannot do this in DOM, because if there’s an error, DOM will not process anything. ---
**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\ **Post date:** [September 30, 2008, 6:48pm UTC](https://www.ruby-forum.com/t/rexml-exceptions/149811/6 "2008-09-30T18:48:18Z")
Actually, this isn’t working for me. I’m using the SAX parser, and it just calls Listener#on\_parser\_error with a string. Not helping me. ---
**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\ **Post date:** [September 30, 2008, 8:53pm UTC](https://www.ruby-forum.com/t/rexml-exceptions/149811/7 "2008-09-30T20:53:29Z")
Also, I don’t think those error messages can help me location the position in the string of the bad XML. They’re pretty, for sure, but not very useful to anyone but a human. ---
**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\ **Post date:** [September 30, 2008, 8:55pm UTC](https://www.ruby-forum.com/t/rexml-exceptions/149811/8 "2008-09-30T20:55:55Z")
On Sep 30, 2:09 pm, Eric W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > My situation requires SAX, unfortunately. > > I need to parse and react to each tag as in comes in. If there’s a > broken one, all tags up to the broken one must be processed, and the > broken one must be stored. I cannot do this in DOM, because if there’s > an error, DOM will not process anything. If you can receive an entire document at a time, libxml has a ‘recover’ mode that will correct what it can and process the entire document – even if it is not well-formed. It works surprisingly well. Another option is writing your own recursive descent parser. See [http://snippets.dzone.com/posts/show/2190](http://snippets.dzone.com/posts/show/2190) for a starting point. – Mark.