# REST - HTTP headers - XML Error Handling -ActiveResource

**URL:** <https://www.ruby-forum.com/t/rest-http-headers-xml-error-handling-activeresource/91728>\
**Category:** Rails\
**Created:** [April 11, 2007, 10:11pm UTC](https://www.ruby-forum.com/t/rest-http-headers-xml-error-handling-activeresource/91728 "2007-04-11T22:11:14Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![eblatt](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/7bcc69/32.png) [@eblatt](https://www.ruby-forum.com/u/eblatt)\
**Post date:** [April 11, 2007, 10:11pm UTC](https://www.ruby-forum.com/t/rest-http-headers-xml-error-handling-activeresource/91728/1 "2007-04-11T22:11:14Z")

</div>

Hi,

I’m putting together a RESTful API that I would like to play nice with  
ActiveResource. I’ve got things mostly working, but I’m beginning to  
stumble around error handling and I’m seeking some thoughtful input.

Here’s some context:

(For a detailed look at the issue I’m contemplating see:  
[O'Reilly Media - Technology and Business Training](http://www.oreillynet.com/onlamp/blog/2003/12/restful_error_handling.html))

Let’s say that I have a REST controller containing code that looks like  
this:

def create  
@book = @book(params[:book])  
respond\_to do |format|  
if false @book.save  
format.xml { head :created, :location =\> book\_url(@book) }  
else  
format.xml { head 400, :xml=\> ErrorCode.new(20, “Save  
failed.”).to\_xml }  
end  
end  
end

(note, I’m _deliberately_ forcing a failure response with ‘if false’ )  
When I execute this method via CURL, I get following (correct, I  
believe) response:

#—  
t$ curl -i -X POST [http://0.0.0.0:3001/books.xml](http://0.0.0.0:3001/books.xml)  
HTTP/1.1 400 Bad Request  
Connection: close  
Date: Wed, 11 Apr 2007 19:46:11 GMT  
Set-Cookie: \_adiserver\_session\_id=dbe7f61d877a041c3d5d49c29d0086e5;  
path=/  
Status: 400 Bad Request  
Xml: \<?xml version="1.0" encoding="UTF-8"?\>  
`
20
Could not save book
save failed.
`  
#—

This response looks correct me because it has:

1. an HTTP Status code
2. some descriptive XML

Seeing this, I expect that ActiveResource should be happy…

but, alas, when doing a @book.save over ActiveResource (console), I get:

@book.save

ActiveResource::ResourceNotFound: Failed with 404  
from/script/…/config/…/config/…/vendor/rails/  
activeresource/lib/active\_resource/connection.rb:92:in `handle\_response’

etc…

Now I would expect to get ‘false’ and/or the the XML containing the  
error information that I’ve constructed.

–OR–

My questions are these:

1. What does ActiveResource expect in the case of failed operation?
2. In the event of a failed request, how does AR get access to the  
supplemental XML that is sent? Is this possible?
3. Are some of my assumptions incorrect?

Perhaps “ActiveResource::ResourceNotFound” is an exception that I need  
to handle in the following manner:

begin  
@book.save  
rescue  
[…could not save code here …]  
end

I look forward to your thoughtful guidance.