For information: See therecommendations by Ethan Cerami: Specialties: Cancer genomics, bioinformatics, scientific computing, software engineering, project management. https://www.linkedin.com/in/ecerami http://www.oreilly.com/pub/au/806
Read: http://archive.oreilly.com/pub/post/restful_error_handling.html#__federated=1 Quoting: Conclusion: * *Human Readable Error Messages:* Part of the major appeal of REST based web services is that you can open any browser, type in the right URL, and see an immediate response -- no special tools needed. However, HTTP error codes do not always provide enough information. For example, if we take option 1 above, and request and invalid book ID, we get back a 404 Error Code. From the developer perspective, have we actually typed in the wrong host name, or an invalid book ID? It's not immediately clear. In Option 3 (DAS), we get back a blank page with no information. To view the actual error code, you need to run a network sniffer, or point your browser through a proxy. For all these reasons, I think Option 4 has a lot to offer. It significantly lowers the barrier for new developers, and enables all information related to a web service to be directly viewable within a web browser. * *Application Specific Errors:* Option 1 has the disadvantage of not being directly viewable within a browser. It also has the additional disadvantage of mapping all HTTP error codes to application specific error codes. HTTP status codes are specific to document retrieval and posting, and these may not map directly to your application domain. For example, one of the DAS error codes relates to invalid genomic coordinates (sequence coordinate is out of bounds/invalid). What HTTP error code would we map to in this case? * *Machine Readable Error Codes:* As a third criteria, error codes should be easily readable by other applications. For example, the XooMLe application returns back only human readable error messages, e.g. "Invalid Google API key supplied". An application parsing a XooMLe response would have to search for this specific error message, and this can be notoriously brittle -- for example, the XooMLe server might simply change the message to "Invalid Key Supplied". Error codes, such as those provided by DAS are important for programmatic control, and easy creation of exceptions. For example, if XooMLe returned a 1001 error code, a client application could do a quick lookup and immediately throw an /InvalidKeyException./ Based on these three criteria, here's my vote for best error handling option: * Use HTTP Status Codes for problems specifically related to HTTP, and not specifically related to your web service. * When an error occurs, always return an XML document detailing the error. * Make sure the XML error document contains both an error code, and a human readable error message. For example: <?xml version="1.0" encoding="UTF-8" ?> <error> <error_code>1001</error_code> <error_msg>Invalid Google API key supplied</error_msg> </error> By following these three simple practices, you can make it significantly easier for others to interface with your service, and react when things go wrong. New developers can easily see valid and invalid requests via a simple web browser, and programs can easily (and more robustly) extract error codes and act appropriately. The Amazon.com web services API follows the approach of returned XML document can specify an /ErrorMsg/ element. XooMLe also follows this approach. (XooMLe provides a RESTful API wrapper to the existing SOAP based Google API). Another approach is by DAS ( Distributed Annotation System) which always returns 200 if there was no HTTP-error and has error information in the HTTP-header, which is less favorable, because it is not human readable, as a browser does not display the HTTP-header. --- End Quoting Best regards Bert -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openehr.org/pipermail/openehr-technical_lists.openehr.org/attachments/20150118/c46a8d6f/attachment.html>
