Re: [scim] [INPUT REQUESTED] Re: Detailed error and status codes

[David Möbius <[e-mail]>]

scimType is good, I just think that another type would be great. The
names themself are not important for me.

I think to generate a Exception message in the needed language would not
be a part of the server. Every client should create their own exception
messages. This way it is easy to translate my homepage to an other
language. The scim server should only create exception messages in one
standard language which would be english.

Am 26.06.2014 17:34, schrieb Phil Hunt:
> 1. scimType is intended to indicate many of these details. Like a unique index conflict (e.g. “uniqueness”).  That said, I’m not sure it would indicate which attribute caused the failure.  Should we indicate which attribute is not unique or which attribute has a mutability error through another response element?
> 
> 2. Why isn’t the standard accept-langauge headers not appropriate to localize the detail message? 
> 
> There are also some security considerations here in cross-domain scenarios. It is very likely that even if we mandate detail errors that many SPs will return generic Status 400 errors to non-privledged clients.
> 
> Phil
> 
> @independentid
> www.independentid.com
> [e-mail]
> 
> 
> 
> On Jun 26, 2014, at 2:09 AM, David Möbius <[e-mail]> wrote:
> 
>> Hello,
>>
>> I would like to adjust to add a "error group" type to the error object.
>>
>> Example:
>>
>> {
>>  “schema”: "urn:scim:api:messages:2.0:Error”
>>  "scimGroupType" - "saving user"
>>  "scimDetailType" - "username allready taken"
>>  "status" - the HTTP status (should correspond to the response header)
>>  "detail" - "The username 'marissa' is already taken"
>> }
>>
>>
>> The scimGroupType and the scimDetailType should never change if you do
>> the same mistage to make it machine readable.
>>
>> Example and Reason:
>> I have a mask where the user can create an account. I have created my
>> html page the way that the user can't do "anything" wrong. The only
>> think the could do wrong is to use a existing username.
>>
>> After I send the new user to the backend I get an exception. Since I
>> wan't to display the exception message in german or an other language I
>> need to know what type of exception was the problem.
>>
>> I would like to give the User kind of messages:
>>
>> 1. The user used a given username: If this is the problem I can see it
>> with the help of the scimDetailType which will always be "username
>> already taken".
>>
>> 2. It is somethink wrong with the userdata (for example a email without
>> @ which I forget to check in my frontend). That something is wrong with
>> the userdata in generall I can see with the "scimGroupType"
>>
>> 3. Something else happens and I want to log the exception in my logs and
>> give an general message to the user
>>
>> In my front end it could look like
>>
>> if(scimException.getScimDetailType.equals("username allready taken")){
>>
>> errorMessage = "in german: Your username is already taken. Plase use a
>> other one."
>> }else if(scimException.getScimGroupType.equals("saving user")){
>>
>> errorMessage = "in german: Could not save your data. Please check your
>> given data.";
>> }else{
>>
>> log.Error(scimException);
>> errorMessage= "in german: an error happen. Please try again later."
>> }
>>
>> For this reason it would be good if we have 2 error codings in our error
>> json object. What do you think about this?
>>
>> by David
>>
>> Am 25.06.2014 21:07, schrieb Phil Hunt:
>>> On the call today (Erik, Bjorn, Morteza, and myself), we discussed the
>>> error issue.
>>>
>>> The major concern with the draft suggested by Julian is really one of
>>> timing - we would prefer not to hold SCIM up. A good middle-ground
>>> approach is to align with the draft, but define the error fully within
>>> SCIM (using the SCIM mime type and schema namespace).
>>>
>>> The proposal on the call is to SCIM mime/type of application/scim+json
>>> in error responses and include the SCIM error message schema declaration.  
>>>
>>> {
>>> “schema”: "urn:scim:api:messages:2.0:Error” (indicates the SCIM message
>>> type)
>>> "scimType" - a keyword indicating the detail error (e.g.  “mutability”)
>>> "status" - the HTTP status (should correspond to the response header)
>>> "detail" - a detailed, human-readable message
>>> }
>>>
>>> Servers MAY return additional attributes (e.g. ones from http-problem
>>> draft).  The only mandatory attributes are “schema” and “status”.  For
>>> example on anonymous self-registration scenarios, servers may be
>>> unwilling to give detail error responses for security reasons.
>>>
>>> The reason for using scimType (instead of type) is to avoid any
>>> confusion with “type” from draft-nottingham-http-problem and its
>>> eventual use of “type”.
>>>
>>> In a future update to SCIM we can then transition to align with the HTTP
>>> Problem draft by simply adding “type” in the way it defines. 
>>>
>>> Phil
>>>
>>> @independentid
>>> www.independentid.com <http://www.independentid.com>
>>> [e-mail] <mailto:[e-mail]>
>>>
>>>
>>>
>>> On Jun 25, 2014, at 12:25 AM, Erik Wahlström
>>> <[e-mail] <mailto:[e-mail]>>
>>> wrote:
>>>
>>>> So that would make it look like the following right?
>>>>
>>>> {
>>>>  "schemas": ["urn:scim:api:messages:2.0:Error"],
>>>>  "Error":
>>>>    {
>>>>      "type": "urn:scim:api:error:2.0:mutability",
>>>>      "title": “Attribute is readOnly.",
>>>>      "detail": “Attribute 'id' is readOnly and can’t be changed in a
>>>> PATCH request.",
>>>>      “status": 400  
>>>>    }
>>>> }
>>>>
>>>> I replaced Errors with Error.
>>>> Also replaced urn:scim:error:api:2.0:mutability with
>>>> urn:scim:api:error:2.0:mutability
>>>>
>>>> That works for me.
>>>> / Erik
>>>>
>>>>
>>>>
>>>> On 25 Jun 2014, at 01:30, Phil Hunt <[e-mail]
>>>> <mailto:[e-mail]>> wrote:
>>>>
>>>>> Note: July 04 is the LAST day for us to potentially submit updates
>>>>> for the IETF90 meeting.  This gives us about 1.5 weeks to close off
>>>>> the error issues and update the drafts.  If you have a moment please
>>>>> take a look and comment as soon as possible...
>>>>>
>>>>> Julian thanks for the suggestion.  For the rest of the group’s
>>>>> benefit, the draft Julian referenced suggests the following
>>>>> attributes be returned in a standardized detailed error JSON body…
>>>>>
>>>>>>   A problem details object MAY have the following members:
>>>>>>
>>>>>>   o  "type" (string) - An absolute URI [RFC3986 <http://tools.ietf.org/html/rfc3986>] that identifies the
>>>>>>      problem type.  When dereferenced, it SHOULD provide human-readable
>>>>>>      documentation for the problem type (e.g., using HTML
>>>>>>      [W3C.REC-html401-19991224 <http://tools.ietf.org/html/draft-nottingham-http-problem-06#ref-W3C.REC-html401-19991224>]).  When this member is not present, its
>>>>>>      value is assumed to be "about:blank".
>>>>>>   o  "title" (string) - A short, human-readable summary of the problem
>>>>>>      type.  It SHOULD NOT change from occurrence to occurrence of the
>>>>>>      problem, except for purposes of localisation.
>>>>>>   o  "status" (number) - The HTTP status code ([RFC2616], Section 6 <http://tools.ietf.org/html/rfc2616#section-6>)
>>>>>>      generated by the origin server for this occurrence of the problem.
>>>>>>   o  "detail" (string) - An human readable explanation specific to this
>>>>>>      occurrence of the problem.
>>>>>>   o  "instance" (string) - An absolute URI that identifies the specific
>>>>>>      occurrence of the problem.  It may or may not yield further
>>>>>>      information if dereferenced.
>>>>>
>>>>> Here is the corresponding example error response:
>>>>>>   HTTP/1.1 403 Forbidden
>>>>>>   Content-Type: application/problem+json
>>>>>>   Content-Language: en
>>>>>>
>>>>>>   {
>>>>>>    "type": "http://example.com/probs/out-of-credit",
>>>>>>    "title": "You do not have enough credit.",
>>>>>>    "detail": "Your current balance is 30, but that costs 50.",
>>>>>>    "instance": "http://example.net/account/12345/msgs/abc",
>>>>>>    "balance": 30,
>>>>>>    "accounts": ["http://example.net/account/12345",
>>>>>>                 "http://example.net/account/67890"]
>>>>>>   }
>>>>>
>>>>> Julian, what is the value of having “type” be a URI?  Why not just
>>>>> have a SCIM specific attribute (scimType) and use simple keywords?
>>>>> (asking mainly for the WG’s benefit). I guess the strong case is that
>>>>> by standardizing HTTP responses, client code gets simplified.
>>>>> However, using standard attributes creates the namespace conflict
>>>>> issue.  So we need URI based error codes.
>>>>>
>>>>> The SCIM specs could adopt the “type”, “detail”, and “status”. We
>>>>> would register a namespace of urn:scim:error:apil:2.0 in the SCIM
>>>>> IANA section in addition to api:messages, schema:core, etc.  This
>>>>> would give detail error types of:
>>>>>  urn:scim:error:api:2.0:mutability, urnscim:error:api:2.0:filter, etc.
>>>>>
>>>>> The other items, like title, instance, etc could be optional or just
>>>>> omitted from SCIM spec. —> we would just indicate that clients should
>>>>> expect attributes within the JSON message other than those defined by
>>>>> the SCIM drafts.
>>>>>
>>>>> IMPORTANT NOTE:  the format suggested by Julian allows for only one
>>>>> error at a time.  Erik had commented he prefers to return only one. I
>>>>> tend to agree. In the case of BULK requests, this is not really an
>>>>> issue since each BULK operation gets its own response block.
>>>>>
>>>>> *_In the interests of time, any objections to using type (with URI
>>>>> based error codes), detail, status, per above and limiting to ONE per
>>>>> response?  _*
>>>>>
>>>>> I know these are normative changes….however I’m pretty sure we can’t
>>>>> avoid changes in the final document clean up whether or not we adopt
>>>>> the proposed standardized error response.
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Phil
>>>>>
>>>>> @independentid
>>>>> www.independentid.com <http://www.independentid.com/>
>>>>> [e-mail] <mailto:[e-mail]>
>>>>>
>>>>>
>>>>>
>>>>> On Jun 24, 2014, at 12:23 PM, Julian Reschke <[e-mail]
>>>>> <mailto:[e-mail]>> wrote:
>>>>>
>>>>>> On 2014-06-24 21:01, Phil Hunt wrote:
>>>>>>> With regards to tickets 37, 46, 67, it looks like we will have some
>>>>>>> normative changes required.  I am also expecting new SCIM error
>>>>>>> codes as
>>>>>>> we look at the possible reasons a server might return Bad Request or
>>>>>>> other HTTP status codes.
>>>>>>>
>>>>>>> Currently, the example response from PATCH, we use “error” to
>>>>>>> indicate a
>>>>>>> detailed error.
>>>>>>>
>>>>>>> * "error":"mutability"*
>>>>>>>
>>>>>>> From Response Codes Section, no detail error is defined:
>>>>>>>
>>>>>>> *HTTP/1.1 404 NOT FOUND*
>>>>>>>
>>>>>>> {
>>>>>>>  "schemas": ["urn:scim:api:messages:2.0:Error"],
>>>>>>>  "Errors":[
>>>>>>>    {
>>>>>>>      *"description":"Resource 2819c223-7f76-453a-919d-413861904646
>>>>>>> not found",
>>>>>>>      "code":"404"*
>>>>>>>    }
>>>>>>>  ]
>>>>>>> }
>>>>>>>
>>>>>>>
>>>>>>> Doing a search around Twitter, AWS, and many others, I see that “code”
>>>>>>> is often used to indicate a detailed error message (“mutability”) and
>>>>>>> status is used to indicate HTTP status.
>>>>>>>
>>>>>>> In an attempt to bring consistency across the API document, I am
>>>>>>> proposing we use http_status and scim_code. This will help make clear
>>>>>>> what we are referring to and allow existing implementations to co-exist
>>>>>>> for a while (by having different names).
>>>>>>>
>>>>>>> _Are there any objections to normalizing the spec around following
>>>>>>> format and attributes?_
>>>>>>>
>>>>>>> Proposed example:
>>>>>>>
>>>>>>> *HTTP/1.1 400 Bad Request*
>>>>>>>
>>>>>>>   Content-Type: application/scim+json;charset=UTF-8
>>>>>>>   Cache-Control: no-store
>>>>>>>   Pragma: no-cache
>>>>>>>
>>>>>>>   {
>>>>>>>     "schemas": ["urn:scim:api:messages:2.0:Error"],
>>>>>>>     "Errors":[
>>>>>>>       {
>>>>>>>         *“scim_code":"mutability”,*
>>>>>>>
>>>>>>> *          “http_status”:400,*
>>>>>>>         "error_description":"Attribute 'id' is readOnly."
>>>>>>>       },
>>>>>>>
>>>>>>>        . . .
>>>>>>>
>>>>>>>     ]
>>>>>>>
>>>>>>>   }
>>>>>>> ...
>>>>>>
>>>>>> You may want to read
>>>>>> <http://tools.ietf.org/html/draft-nottingham-http-problem-06>...
>>>>>>
>>>>>> Best regards, Julian
>>>>>>
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>>>>>
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