Please note that this challenge is closed. The deadline for receiving a badge upon successful completion has passed. Check out this new challenge for the month of August.
Welcome to the fourth and final week of this month's SAP Developer Challenge. This week we are going to learn about consuming remote services with the SAP Cloud Application Programming Model.
If you haven't read the announcement blog post for this challenge, please head over and do so. This week's challenge builds on top of previous three challenges, which you should have completed before starting with this one.
The Challenge
We have already come a long way with our application since week 1 of the challenge. We have a solid data model, load initial data and can track golf rounds, but still there is one central component missing - the golf players. Wouldn't it be nice to track who played a round of golf? The simplest approach here would be to create a new entity in our data model, but I think we should use this as an opportunity to learn how to consume remote services. The remote service that we are going to consume exposes the API of this SAP Community Groups platform, because the players will be you folks! We will integrate an remote service that lists everyone who completed week 1 of this challenge successfully, and these community members will be the "golf players".
This is what you have to do to successfully complete this week's challenge:
1. Check out the service that we are going to consume: https://developer-advocates-free-tier-central-hana-cloud-instan3abe9a0e.cfapps.us10.hana.ondemand.co...
2. Copy the following metadata information from the remote service into a new file RemoteService.edmx in the root of your project. CAP will need this information to know how to integrate the remote service:
<edmx:Edmx xmlns:edmx="http://docs.oasis-open.org/odata/ns/edmx" Version="4.0">
<edmx:Reference Uri="https://oasis-tcs.github.io/odata-vocabularies/vocabularies/Org.OData.Capabilities.V1.xml">
<edmx:Include Alias="Capabilities" Namespace="Org.OData.Capabilities.V1"/>
</edmx:Reference>
<edmx:Reference Uri="https://sap.github.io/odata-vocabularies/vocabularies/Common.xml">
<edmx:Include Alias="Common" Namespace="com.sap.vocabularies.Common.v1"/>
</edmx:Reference>
<edmx:Reference Uri="https://oasis-tcs.github.io/odata-vocabularies/vocabularies/Org.OData.Core.V1.xml">
<edmx:Include Alias="Core" Namespace="Org.OData.Core.V1"/>
</edmx:Reference>
<edmx:DataServices>
<Schema xmlns="http://docs.oasis-open.org/odata/ns/edm" Namespace="CatalogService">
<EntityContainer Name="EntityContainer">
<EntitySet Name="Players" EntityType="CatalogService.Players"/>
</EntityContainer>
<EntityType Name="Players">
<Key>
<PropertyRef Name="name"/>
</Key>
<Property Name="name" Type="Edm.String" Nullable="false"/>
</EntityType>
<Annotations Target="CatalogService.EntityContainer/Players">
<Annotation Term="Capabilities.DeleteRestrictions">
<Record Type="Capabilities.DeleteRestrictionsType">
<PropertyValue Property="Deletable" Bool="false"/>
</Record>
</Annotation>
<Annotation Term="Capabilities.InsertRestrictions">
<Record Type="Capabilities.InsertRestrictionsType">
<PropertyValue Property="Insertable" Bool="false"/>
</Record>
</Annotation>
<Annotation Term="Capabilities.UpdateRestrictions">
<Record Type="Capabilities.UpdateRestrictionsType">
<PropertyValue Property="Updatable" Bool="false"/>
</Record>
</Annotation>
</Annotations>
</Schema>
</edmx:DataServices>
</edmx:Edmx>
3. We can now properly import this metadata into our project (CDS import API) by running the following command from the root of our project: cds import RemoteService.edmx
4. Explore the newly generated srv/external/ directory. It contains the previously used edmx file as well as a newly generated Schema Notation (CSN) file, which is a "notation for compact representations of CDS models".
5. Inspect the changes that were made to the package.json. There was a new cds.requires.RemoteService section added to make CDS aware of the remote service we imported and are about to use in the next steps.
6. Add a new file .env (don't forget the leading dot) to the project root. This file is usually used to define environment variables that will automatically get picked up by CDS. Although we will not store real credentials in this file (or anywhere else in this project), this file would be a good place to do that. It is important to never commit this file to any source code control system (like git).
7. Add the following code to the newly created .env, which adds the service url as "credentials" to the remote service definition:
cds.requires.RemoteService.credentials.url=https://developer-advocates-free-tier-central-hana-cloud-instan3abe9a0e.cfapps.us10.hana.ondemand.com/browse/
8. Replace the content of the srv/cat-service.cds with the following code. This service definition uses the remote service (line 2) and integrates its "Players" entity into our CatalogService (line 5):
using { golf } from '../db/schema';
using { RemoteService as external } from './external/RemoteService';
service CatalogService @(path:'/browse') {
entity Players as projection on external.Players;
entity Rounds as projection on golf.Rounds;
entity Holes as projection on golf.Holes;
entity Shots as projection on golf.Shots;
}
9. Add the following code to the main exported function of the srv/cat-service.js, which is our service handler file from last week. This code makes sure that all incoming request to the "Players" entity will in fact get forwarded to the RemoteService:
const remote = await cds.connect.to('RemoteService')
this.on('*', 'Players', (req) => {
console.log('>> delegating to remote service...')
return remote.run(req.query)
})
10. Start the cds server like usual and inspect the console output. You should see that CDS is connecting to the url of the RemoteService.
11. Share a screen shot of the CatalogService running on your localhost and exposing the remote "Players" entity with its data. It should look something like this:
Resources
We have gathered a few helpful resources for this week's challenge. Feel free to use the comments sections if you have question or need help.
- Consume remote services
- CDS import API
- SAP CodeJam: Service integration with SAP Cloud Application Programming Model
Further Learning
As this week marks the end of this SAP Developer Challenge, here is some inspiration for how you could further improve the application:
- Add authentication
- Restrict access with user claims
- Add an SAP Fiori user interface
- Mashup the local and remote service with associations
We hope you enjoyed this SAP Developer Challenge and learned something new. Feel free to share feedback and your experience in the comment section down below or via a private message!
Good luck and happy learning!
Here is my submission for week 4 :
Regards,
Ashok
Hi, my browser Microsoft Edge does not have the same JSON parsing tools built-in, or at least one that I 'am aware of, but the output should be the same. Is this alright?
hello!
This is my submission for week 4:
My submission for week 4
Console
Here is my submission:
Had to run the following to make it work (using cds-ts as I hate vanilla javascript):
npm i --save @Former Member-cloud-sdk/resilience
npm i --save @Former Member-cloud-sdk/http-client 
I also had a problem with modules @Former Member-cloud-sdk/resilience and @Former Member-cloud-sdk/http-client . If anybody has such problem, just install these modules.
🙂
Last submission:
Console:
Thank you for the challenge, it was certainly interesting, mainly for a beginner like me!
Hi @nicoschoenteich ,
This is my submission for week#4 challenge.
Once again, I have learned so much from this challenge. Thanks everybody especially the developer advocate team to bring this idea on the table to help us in SAP development learning journey.
Thanks,
Wises
Here is my submission for week 4. I started learning CAPM during this challenge and it was fun. Thanks to the developer advocate team for the challenge.
Herei s my submission for week 4 (I did complete week 1 😎)
I was getting this error while runnign the application - had to add '@sap-cloud-sdk/http-client' package to make it work
Thanks @nicoschoenteich for these challenges. They were a great starting steps to CAP introducing many important concepts. All the while, I couldn't help but compare it to how RAP development workflow is.
Regards
Dhananjay
My Submission for week 4. Thank you!
My week 4 submission
My Github repo for this project : https://github.com/meriemso/cap_challenge_07_23
Thanks for this challenge !
My week 4 submission. Look forward to your verification 😃
Hi Nico,
Thanks for organizing the challenge.
Here is my submission.
