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jiwanovski
Level: Powered On

CustomConnector etag parameter

Hi everbody,

I cam creating a custom connector to connect with a partner solution of Microsoft Dynamics Business Central.

Business Central provie some API features which is the base for the custom connector.

 

Scenario:

- Types of Request: GET, POST and PATCH

- GET and POST Request are working fine on every part: Postman, CustomConnector Test Area and PowerApps

- PATCH Request is only working with POSTMAN and Custom Connector Test Area. On PowerApps I always get the information, that another user has already changed the record. 

 

Detail information on Patch:

- To send the PATCH Request I need to send the information / node "etag" with the request

- The "etag" information is placed within the header and the key "If-Match"

 

Screenshot of the parameter setup for "If-Match" on CustomConnector

2019_07_22_12_49_17_PowerApps.png

Currently I assume that this setup may cause this error because of Type = string. 

Has anybody else worked with API, PATCH Request and "If-Match" yet?

1 ACCEPTED SOLUTION

Accepted Solutions
Sijts
Level 8

Re: CustomConnector etag parameter

in base, all version of BC work in general.

 

The message you get is purely from a wrong inputted etag.

check in your get comment if the @odata.etag is Type:string Format: ""

Same for the if-Match parameter Type: string Format: ""

 

Also do you patch the same entity as where the get is from?

Etags are page related, so if you get from a different page then to which you patch you also may experience the error

 

View solution in original post

6 REPLIES 6
Sijts
Level 8

Re: CustomConnector etag parameter

Hi jiwanovski,

 

You are almost there.

The etag is a dynamic feature of a record, it says which "version" of the record you want to modify.

if the current version of bc and your version are a match than the modification is allowed.

 

so what you want to do is:

-http (get) the latest E-tag of the record you want to modify 

- http(Patch) the just received e-tag in the if-Match.

 

This way BC accepts your change because your change is based on the latest "version"

 

jiwanovski
Level: Powered On

Re: CustomConnector etag parameter

Hi @Sijts 

thank you for your quick response. 

Aktually I do this already, but I still get the message, that some User has changed the dataset before. 

 

What I am doing:

- First I get a set of records of a table with a GetRequest

- This is assigned as Item for a gallery

- In gallery I have some controls to modify single fields and an icon to save

- With the OnSelect of the icon I try to do the PATCH. Here I just reference to the ThisItem.'@odata.etag' to give the etag information....

 

But I still get the error message "Another user has changed the record"....

 

Any idea what I should test?

Which version of BC have you tested (which client build?)

Sijts
Level 8

Re: CustomConnector etag parameter

in base, all version of BC work in general.

 

The message you get is purely from a wrong inputted etag.

check in your get comment if the @odata.etag is Type:string Format: ""

Same for the if-Match parameter Type: string Format: ""

 

Also do you patch the same entity as where the get is from?

Etags are page related, so if you get from a different page then to which you patch you also may experience the error

 

View solution in original post

Community Support Team
Community Support Team

Re: CustomConnector etag parameter

Hi @jiwanovski ,

Have you taken a try to remove the "W/" prefix from the ETag value (default value) you set for the If-Match header in your Patch request?

 

Please consider take a try to remove the  "W/" prefix from the ETag value (default value) you set for the If-Match header in your Patch request, then try your custom connector again, check if the issue is solved.

 

In addition, the ETag value of the "If-Match" header is required to provide a string of ASCII characters rather than a HTML text. Please check the following article for more details:

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag

Please consider set Format property to Blank as below:1.JPG

 

Please take a try with above solution, then check if the issue is solved.

 

Best regards,

Community Support Team _ Kris Dai
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
Highlighted
jiwanovski
Level: Powered On

Re: CustomConnector etag parameter

Hi everbody,

 

I agree that this should be a format problem of the etag value. 

For the GET and the PATCH request I use the same API Page. So I have believed that I just can take the value from GET response. 

 

I also modified the etag parameter to String blank (GET and PATCH) again. This was the value by default (I just changed this in case of testing purpose). 

 

I also tried to eleminate the removing the prefix "w/" value and set this to header with "If-Match" or just do put the "@odata.etag" direct into the Body.... Nothing helped... 

 

What I wonder if there is anything on the value of the GET response itself wrong?

This is how it looks like in Postman

 

"@odata.etag": "W/\"JzQ0O1c1a1JkaDE3RW80QUxsR3FkVm0rNGZOUDJSekNSN0VXdkI0RlpyN0NWNXM9MTswMDsn\""

I also tried to just remove the "\" in this string...

Any other ideas?

jiwanovski
Level: Powered On

Re: CustomConnector etag parameter

Hi everybody,

 

@Sijts and I just had a short call on that and he was already right before.

When I tried to send the PATCH Request, I hadn't the correct etag value in place.

 

How it is not working:

(1) Get a list of records (including a etag value) with somethink like: https://yourURL.com/BC130/api/V1/API/beta/companies/:companyId/APIEntity?$filter=ID eq dbeb2692-1fa6-490d-9f54-147a3e422a5e

(2) Add this to a gallery

(3) Add Buttion to do the PATCH Request

(4) In OnSelect calling PATCH Request like: https://yourURL.com/BC130/api/V1/API/beta/companies/:companyId/APIEntity/:entityID

 

If you do it like this way, you will get always that another user has changed the record.

Before you do Step (4) you have to do a single API Request like: https://yourURL.com/BC130/api/V1/API/beta/companies/:companyId/APIEntity/:entityID

 

So even both GET Request are based on the same Page in BC I first have to do the GET statement for the single record and take the etag value from there. Then it is running.

 

So many thanks to @Sijts!!!!

The solved answer should get to you! 

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