REST services are services that are executed by connecting to an URL that defines operation and parameters then it returns an answer – not seldom as JSon objects.

You must set the tagged value RestAllowed on ViewModels you want to allow Rest access to.

Calling existing REST services

MDriven supports a couple of EAL operators to manage REST services. All operators reside on the selfVM variable – available only in the ViewModel context.

selfVM.RestGet(targeturl,user,pwd,optionalnestingwithheaders)

selfVM.RestPost(targeturl,user,pwd,optionalnestingwithheadersAndUploadValues)

selfVM.RestDownload(targeturl,user,pwd,optionalnestingwithheaders)

There is a also a new helper operator on selfVM:

selfVM.JSonToObjects( «<Type>» ,  JSonDataInStringFormat)

The selfVM.JSonToObjects creates objects of class Type and matches attributes and association from the json data – and it can create object trees (unclosed graphs) by following names on associations. These few additions enables us to consume Rest services that others expose.

Example

Here is a real life example

First Action GetExporttest retrieves data by converting another viewmodel to xml - it stores it in the variable vText

Next action invokes RestPost to send that data to an url-address, it also says that it should look at the nesting named 'Xml' - in this nesting we have the STRINGCONTENT (see also OCLOperators RestPost) data and we assign it to vText - we also add the header Authorization with a bearer token in order to get access from the receiving service.

Exposing ourselves as a REST service

And when it comes to exposing ourselves to others – Turnkey has two new MVC verbs:

TurnkeyRest/Get?command=vmname&id=rootobjref

TurnkeyRest/Post?command=vmname&id=rootobjref

NOTE! the correct controller name is TurnkeyRest - this was earlier MDrivenRest

What they do is that they look for ViewModel named as the command-parameter, if one is found the accessgroups are checked to see if access is allowed. If it is, additional parameters sent in the url are matched against ViewModel variables – and given corresponding values. Then any actions present in the root level of the ViewModel are executed. Then the Get verb packs the viewmodel content as json in the response.

The Post verb looks in the request values after names that match the ViewModel root – if match is found the corresponding value is applied. Then changes – if any – are committed to db. The last thing for post is that it packs the complete ViewModel as json in the response. If there is an error – a string “error: <message>” is returned.

Video

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What is REST? How does it work with MDriven turnkey? calling an existing REST service exposing ourself as REST service MDriven turnkey app slot how to expose information as the Rest service? MDriven Rest/get strategy how to consume data? selfvm Rest/Get operator hard-coded objects Json to objects operator update data with allow post RestPost operator as a post command operation execution vSomeParam adding new parameters