I'm working on a project that uses the new Web API and I noticed somebody is returning an IQueryable<T> from a Get method.
My understanding is that IQueryable is useful for improving performance (deferred execution), but I don't think a client on the other end of an HTTP connection is going to be able to take advantage of that.
My gut is telling me that this should be IEnumberable<T>instead. Am I right about this?
Responses to methods returning IQueryable<T> can be "queried" by passing some odata-like parameters in the query string ($top, $skip, $filter, $orderby). For example, if your resource can be found at .../api/People, you can send those requests, which will cause the server to return different data:
.../api/People?$top=10 ==> return only the first 10 elements
.../api/People?$skip=10&$top=5 ==> return the 11th to 15th elements
.../api/People?$filter=Name%20eq%20'John' ==> Only return people named "John"
.../api/People?$orderby=Name&$top=10 ==> return the first 10 elements, ordered by name
Notice that on the beta release any operation which returns IQueryable<T> automatically has this "querying" support added to it. On the latest bits (from codeplex), you need to manually add a [Queryable] attribute to the operation to enable this behavior.
If you don't want that querying behavior, then yes, returning IEnumerable<T> is just fine.
Related
I am currently attempting to use transactions in my C++ app, but I have a problem with the ODBC's auto commit mode.
I am using the POCO libaries to create a connection to a PostgreSQL database on the same machine. Currently, I can send data to this database as single statements, but I cannot get my head around how to use Poco's transaction libraries to be able to send this data more quickly.
As I have several thousand records to insert, and so continuing to use single insert statements is extrememly slow and inpractical - So I am trying to use Poco's transaction to speed this up a bit (a fair bit).
The error I am encountering is a theoretically a simple one - Poco is throwing the following error:
'Invalid access: Session is in auto commit mode.'
I understand, as a result of this, I should somehow set "auto commit" to false - as it only allows me to commit data to the database line by line, rather than as a single transaction.
The problem is how I set this.
Currently, I have a session created from Session.h, that looks alot like this:
session = new Poco::Data::Session(
"ODBC",
connection_data.str()
);
Where connection data is a simple stringstream with the login information, password, database, server and "Driver={PostgreSQL ANSI};" to tell ODBC to utilize PostgreSQL's driver.
I have tried just setting a property "autocommit" to false through the session's setFeature or setProperty settings, this, of course, was to no avail. (it was more of a ditch attempt at this point).
session->setFeature("AUTOCOMMIT", false);
Looking around, I saw a possible alternative method by creating a ODBC sessionImpl directly from ODBC/session/SessionImpl.h instead of using this generic method above, and then creating a new session object from this.
The benefits of this are that ODBC's sessionImpl has references to autocommit mode in the header, which would suggest it would be able to handle this:
void autoCommit(const std::string&, bool val);
/// Sets autocommit property for the session.
However, having not used sessionImpl before, I cannot garuntee if this will work or if can can get this to work with the limited documentation available.
I am using C++ 03 (Not 11), with Visual Studio 2015
Poco 1.7.5
Boost (Where needed)
Would any one know the correct way of setting this feature (above) or a alternative method to achieving this?
edit: Looking at the source of poco, at:
https://github.com/pocoproject/poco/blob/develop/Data/ODBC/src/SessionImpl.cpp#L153
The property seems be named autoCommit, and looking at
https://github.com/pocoproject/poco/blob/develop/Data/include/Poco/Data/AbstractSessionImpl.h#L120
the case of the property names seem to matter. So, does it help if you use session->setFeature("autoCommit", false);?
Cant you just call session->begin(); and session->end(); on the corresponding Session object?
What is returned by session->canTransact()?
According to the doc begin() will start a new transaction, the doc does not mention any property that needs to be set before or after.
See: https://pocoproject.org/docs/Poco.Data.Session.html
Also faced a similar issue.
First of all before begin() need:
m_ses.setFeature("autoCommit", false);
m_ses.begin();
And the second issue is that this feature stays "autoCommit" in false for all other sessions. So don't forget for the next session call
session.setFeature("autoCommit", true);
I need to intercept my loopback queries before they query my Mongodb to add additional filters, for example, to limit the object to what the user has access to.
I can successfully update the query on access operation hook to add filters to the GET /Applications , where Applications is my object. However This fails to work for GET /Applications/count
The command runs with a 200, however it returns zero results, even though I'm adding the exact same filters. There most be something different about count that I'm missing. The ctx object looks have a ton of functions/objects in it. I'm only touching the query property, but there must be something else I need to do.
Any ideas? Thank you, Dan
Could you please share your access hook observer's implementation. I tried it on a sample app, and following access hook works as expected for /api/Books/count:
module.exports = function(Book) {
Book.observe('access', function logQuery(ctx, next) {
ctx.query.where.id = 2; // changing filter value for where
console.log('Accessing %s matching %j', ctx.Model.modelName, ctx.query.where);
next();
});
};
Verify that you're modifying query property of Context (see access hook).
Hope that helps.
http://localhost:8080/myApp/camunda-rest/engine/default/history/process-instance/count?processInstanceBusinessKey=myApp-201010
{
"count": 1
}
If I try to get from REST client it is providing me proper output(if the value exist in database). But I need to get the value from Java application using the below code,
ProcessInstanceRestService pIRS=new ProcessInstanceRestService("default");
ProcessInstanceQueryDto queryParameter=new ProcessInstanceQueryDto();
List<VariableQueryParameterDto> variables=new ArrayList<VariableQueryParameterDto>();
VariableQueryParameterDto variableQueryParameterDto = new VariableQueryParameterDto();
variableQueryParameterDto.setName("processInstanceBusinessKey");//processInstanceBusinessKey
variableQueryParameterDto.setValue("myApp-201010");
variables.add(variableQueryParameterDto);
queryParameter.setVariables(variables);
queryParameter.setParameter("myApp-201010");
CountResultDto cRD=pIRS.queryProcessInstancesCount(queryParameter);
return ""+cRD.getCount();
I am getting count as 0 everytime , Please let me know where I am going wrong
The business key is not a process variable. Also in the REST URL you query for historic process instances but in the code snipped you use the runtime process instance query. There are setter methods for the business key on both runtime (ProcessInstanceQueryDto#setBusinessKey) and history (HistoricProcessInstanceQueryDto#setProcessInstanceBusinessKey) DTOs.
I'm new to OTRS (3.2) and also new to PERL but I have been given the task of setting up OTRS so that it will make a call to our remote webservice so a record can be created on our end when a ticket is set as "Closed".
I set up various dynamic fields so the customer service rep can fill in additional data that will be passed into the webservice call along with ticket details.
I couldn't get the webservice call to trigger when the ticket was "Closed" but I did get it to trigger when the "priority" was changed so I'm just using that now to test the webservice.
I'm just using the Test.pm and TestSimple.pm files that were included with OTRS.
When I look at the Debugger for the Webserice, I can see that the calls were being made:
$VAR1 = {
'TicketID' => '6'
};
My webservice currently just has one method "create" which just returns true for testing.
however I get the following from the Test.pm
"Got no TicketNumber (2014-09-02 09:20:42, error)"
and the following from the TestSimple.pm
"Error in SOAP call: 404 Not Found at /TARGET/SHARE/var/otrs/Kernel/GenericInterface/Transport/HTTP/SOAP.pm line 578 (2014-09-02 09:20:43, error)
I've spent countless hours on Google but couldn't find anything on this. All I could find is code for the Test.pm and TestSimple.pm but nothing really helpful to help me create a custom invoker for my needs and configure the webservice in OTRS to get it to work.
Does anyone have any sample invokers that I can look at to see how to set it up?
Basically I need to pass the ticket information along with my custom dynamic fields to my webservice. From there I can create the record on my end and do whatever processing.
I'm not sure how to setup the Invoker to pass the necessary ticket fields and dynamic fields and how to make it call a specific method in my remote webservice.
I guess getting the Test.pm and TestSimple.pm to work is the first step then I can modify those for my needs. I have not used PERL at all so any help is greatly appreciated.
I'm also struggling with similar set of requirements too. I've also never programmed in PERL, but I can tell you at least that the "Got no TicketNumber" in the Test.pm is right from the PrepareRequest method, there you can see this block of code:
# we need a TicketNumber
if ( !IsStringWithData( $Param{Data}->{TicketNumber} ) ) {
return $Self->{DebuggerObject}->Error( Summary => 'Got no TicketNumber' );
}
You should change all references to TicketNumber to TicketID, or remove the validation whatsoever (also there is mapping to ReturnedData variable).
Invoking specific methods on your WS interface is quite simple (but poorly documented). The Invoker name that you specify in the "OTRS as requester" section of web service configuration corresponds to the WS method that will be called. So if you have WS interface with a method called "create" just name the Invoker "create" too.
As far as the gathering of dynamic field goes, can't help you on that one yet, sorry.
Cheers
I need to do a callout to webservice from my ApexController class. To do this, I have an asycn method with attribute #future (callout=true). The webservice call needs to refeence an object that gets populated in save call from VF page.
Since, static (future) calls does not all objects to be passed in as method argument, I was planning to add the data in a static Map and access that in my static method to do a webservice call out. However, the static Map object is getting re-initalized and is null in the static method.
I will really appreciate if anyone can give me some pointeres on how to address this issue.
Thanks!
Here is the code snipped:
private static Map<String, WidgetModels.LeadInformation> leadsMap;
....
......
public PageReference save() {
if(leadsMap == null){
leadsMap = new Map<String, WidgetModels.LeadInformation>();
}
leadsMap.put(guid,widgetLead);
}
//make async call to Widegt Webservice
saveWidgetCallInformation(guid)
//async call to widge webserivce
#future (callout=true)
public static void saveWidgetCallInformation(String guid) {
WidgetModels.LeadInformation cachedLeadInfo =
(WidgetModels.LeadInformation)leadsMap.get(guid);
.....
//call websevice
}
#future is totally separate execution context. It won't have access to any history of how it was called (meaning all static variables are reset, you start with fresh governor limits etc. Like a new action initiated by the user).
The only thing it will "know" is the method parameters that were passed to it. And you can't pass whole objects, you need to pass primitives (Integer, String, DateTime etc) or collections of primitives (List, Set, Map).
If you can access all the info you need from the database - just pass a List<Id> for example and query it.
If you can't - you can cheat by serializing your objects and passing them as List<String>. Check the documentation around JSON class or these 2 handy posts:
https://developer.salesforce.com/blogs/developer-relations/2013/06/passing-objects-to-future-annotated-methods.html
https://gist.github.com/kevinohara80/1790817
Side note - can you rethink your flow? If the starting point is Visualforce you can skip the #future step. Do the callout first and then the DML (if needed). That way the usual "you have uncommitted work pending" error won't be triggered. This thing is there not only to annoy developers ;) It's there to make you rethink your design. You're asking the application to have open transaction & lock on the table(s) for up to 2 minutes. And you're giving yourself extra work - will you rollback your changes correctly when the insert went OK but callout failed?
By reversing the order of operations (callout first, then the DML) you're making it simpler - there was no save attempt to DB so there's nothing to roll back if the save fails.