Before we begin!
In this 7 blog series, we are going to provide a small end-to-end scenario to work with SAP® CAPM. Here the usecase we are going to use is of Learning Management System(LMS) and build a Student List App and Deploy it to SCF.
Link to Master(or Main) Blog from which all the other blogs can be reached is Here.
In this section we will be creating and running a simple CAPM Service, so lets start!
Step 1: Create a New CAPM Project
cds init <ProjectName>
This will create a Blank project of capm.
You will see 3 main content in the folder:
- package.json
- package-lock.json
- node_modules
On going inside the node_modules folder you will see list of individual modules which got downloaded
root@apples-MacBook-Air:~/Desktop/Blog/capm1/demo1/demop/node_modules$ ls -l
total 0
drwxr-xr-x 3 root staff 102 Nov 21 15:20 @sap
drwxr-xr-x 7 root staff 238 Nov 21 15:20 accepts
drwxr-xr-x 6 root staff 204 Nov 21 15:20 array-flatten
drwxr-xr-x 8 root staff 272 Nov 21 15:20 body-parser
drwxr-xr-x 7 root staff 238 Nov 21 15:20 bytes
drwxr-xr-x 7 root staff 238 Nov 21 15:20 content-disposition
drwxr-xr-x 7 root staff 238 Nov 21 15:20 content-type
drwxr-xr-x 7 root staff 238 Nov 21 15:20 cookie
drwxr-xr-x 7 root staff 238 Nov 21 15:20 cookie-signature
drwxr-xr-x 15 root staff 510 Nov 21 15:20 debug
drwxr-xr-x 8 root staff 272 Nov 21 15:20 depd
drwxr-xr-x 6 root staff 204 Nov 21 15:20 destroy
drwxr-xr-x 6 root staff 204 Nov 21 15:20 ee-first
drwxr-xr-x 7 root staff 238 Nov 21 15:20 encodeurl
drwxr-xr-x 6 root staff 204 Nov 21 15:20 escape-html
drwxr-xr-x 7 root staff 238 Nov 21 15:20 etag
drwxr-xr-x 8 root staff 272 Nov 21 15:20 express
drwxr-xr-x 7 root staff 238 Nov 21 15:20 finalhandler
drwxr-xr-x 7 root staff 238 Nov 21 15:20 forwarded
drwxr-xr-x 7 root staff 238 Nov 21 15:20 fresh
drwxr-xr-x 7 root staff 238 Nov 21 15:20 http-errors
drwxr-xr-x 8 root staff 272 Nov 21 15:20 iconv-lite
drwxr-xr-x 7 root staff 238 Nov 21 15:20 inherits
drwxr-xr-x 7 root staff 238 Nov 21 15:20 ipaddr.js
drwxr-xr-x 7 root staff 238 Nov 21 15:20 media-typer
drwxr-xr-x 7 root staff 238 Nov 21 15:20 merge-descriptors
drwxr-xr-x 7 root staff 238 Nov 21 15:20 methods
drwxr-xr-x 11 root staff 374 Nov 21 15:20 mime
drwxr-xr-x 8 root staff 272 Nov 21 15:20 mime-db
drwxr-xr-x 7 root staff 238 Nov 21 15:20 mime-types
drwxr-xr-x 6 root staff 204 Nov 21 15:20 ms
drwxr-xr-x 8 root staff 272 Nov 21 15:20 negotiator
drwxr-xr-x 7 root staff 238 Nov 21 15:20 on-finished
drwxr-xr-x 7 root staff 238 Nov 21 15:20 parseurl
drwxr-xr-x 7 root staff 238 Nov 21 15:20 path-to-regexp
drwxr-xr-x 7 root staff 238 Nov 21 15:20 proxy-addr
drwxr-xr-x 12 root staff 408 Nov 21 15:20 qs
drwxr-xr-x 7 root staff 238 Nov 21 15:20 range-parser
drwxr-xr-x 8 root staff 272 Nov 21 15:20 raw-body
drwxr-xr-x 7 root staff 238 Nov 21 15:20 safe-buffer
drwxr-xr-x 9 root staff 306 Nov 21 15:20 safer-buffer
drwxr-xr-x 8 root staff 272 Nov 21 15:20 send
drwxr-xr-x 7 root staff 238 Nov 21 15:20 serve-static
drwxr-xr-x 8 root staff 272 Nov 21 15:20 setprototypeof
drwxr-xr-x 8 root staff 272 Nov 21 15:20 statuses
drwxr-xr-x 6 root staff 204 Nov 21 15:20 toidentifier
drwxr-xr-x 7 root staff 238 Nov 21 15:20 type-is
drwxr-xr-x 7 root staff 238 Nov 21 15:20 unpipe
drwxr-xr-x 7 root staff 238 Nov 21 15:20 utils-merge
drwxr-xr-x 7 root staff 238 Nov 21 15:20 vary
Step 2: Content of package.json
If you go inside the package.json, you will see two dependencies
- @sap/cds
- express
{
"name": "demop",
"version": "1.0.0",
"description": "Generated by cds init",
"repository": "<Add your repository here>",
"license": "ISC",
"dependencies": {
"@sap/cds": "^3.18.4",
"express": "^4.17.1"
},
"engines": {
"node": "^8.9"
},
"scripts": {
"build": "cds build/all --clean",
"deploy": "cds deploy",
"start": "cds run"
}
}
Step 3: server.js of @sap/cds
@sap/cds is the module which is inside folder node_modules/@sap/cds.
Here you will find server.js which is actually the file which is run when you execute
a CAP Project with cds run command.
Content inside node_modules/@sap/cds
root@apples-MacBook-Air:~/Desktop/Blog/capm1/demo1/demop/node_modules/@sap/cds$ ls -l
total 928
-rw-r--r-- 1 Ajay staff 25104 Nov 15 21:06 CHANGELOG.md
-rw-r--r-- 1 Ajay staff 746 Nov 15 21:06 README.md
-rw-r--r-- 1 Ajay staff 396160 Nov 18 12:48 SIGNATURE.SMF
drwxr-xr-x 5 Ajay staff 170 Nov 21 15:20 _i18n
drwxr-xr-x 10 Ajay staff 340 Nov 21 15:20 apis
drwxr-xr-x 20 Ajay staff 680 Nov 21 15:20 bin
-rw-r--r-- 1 Ajay staff 3619 Nov 15 21:06 common.cds
-rw-r--r-- 1 Ajay staff 12591 Feb 28 2017 developer-license-3.1.txt
drwxr-xr-x 3 Ajay staff 102 Nov 21 15:20 etc
drwxr-xr-x 12 Ajay staff 408 Nov 21 15:20 lib
drwxr-xr-x 53 root staff 1802 Nov 21 15:20 node_modules
-rw-r--r-- 1 Ajay staff 7293 Nov 15 21:06 npm-shrinkwrap.json
-rw-r--r-- 1 Ajay staff 9574 Nov 21 15:20 package.json
-rw-r--r-- 1 Ajay staff 1517 Nov 15 21:06 server.js
Step 4: Create a simple Service
Create srv
First, we create a folder with name srv inside the project directory
mkdir srv
Create js
then we create a file mySimpleService.js which is going to contain our service
touch mySimpleService.js
Implement js
then, we create a module which holds our service, in simple js we can write as
const exportSRV = function(srv) {
srv.on("somesrv", req => {
return "Hello " + req.data.msg;
});
};
module.exports = exportSRV;
the same code we can write using ES6 and arrow notation as
//this code is same as above but with arrow(=>) function
module.exports = srv => {
srv.on("somesrv", req => {
return "Hello " + req.data.msg;
});
};
Create cds service
Create a new file with name mySimpleService.cds in same folder of srv.
Here the name of the cds file can be different from js file but to keep
track of our service we have named it same
touch mySimpleService.cds
Add Service as function
then, we will add same service name which we exported in above js file
service exportSRV {
function somesrv (msg:String) returns String;
}
Run project
So, far we have two files one js and one cds. Now we come to root of project and
run it with command cds run
cds run
You will see a message in console that server is running in port 4004
apples-MacBook-Air:/Users/apple/Desktop/Blog/camp2/demop# cds run
[cds] - serving exportSRV at /exportsrv - with impl: srv/mySimpleService.js
[cds] - service definitions loaded from:
srv/mySimpleService.cds
[cds] - launched in: 1949.628ms
[cds] - server listening on http://localhost:4004 ...
[ terminate with ^C ]
Open the browser and go to url
http://localhost:4004/exportsrv/somesrv(msg='world')
You will get below output
{
@odata.context: "$metadata#Edm.String",
@odata.metadataEtag: "W/"wF4SeVv7xAHyDG7O8zaA1wEHxkfG89tmiLrYI88n37c="",
value: "Hello world"
}
🙂 Congratulations! You have now a Simple CAP Service Working.
Before we end!
In this 7 blog series, we are going to provide a small end-to-end scenario to work with SAP® CAPM. Here the usecase we are going to use is of Learning Management System(LMS).
Link to Master(or Main) Blog from which all the other blogs can be reached is Here.