Consuming a Business Component exposed as Rest with GeneXus

The different CRUD operations of a BC are accessed through different HTTP methods so as to call a Business Component exposed as Rest.

Methods to call a Business Component exposed as Rest service

• Create: using HTTP POST method.
• Read: using the HTTP GET method.
• Update: using the HTTP PUT method.
• Delete: via the HTTP DELETE method.

Endpoint URI for the Bussiness Component

The endpoint URI for Business components is

 <server uri>/rest/<bc name>

e.g: If "Product" is a BC exposed as Rest, the URI of the service would be: 172.19.12.1/MyApp/rest/Product

If the BC belongs to a module, the endpoint URI is

<server uri>/rest/<module>/<bc name>

For example, if the module is "module2" under "module1", the URI would be: <server uri>/rest/module2/module1/<bc name>.

How to pass the parameters for calling a Rest BC

The parameters have to be separated by commas in the URI.

Depending on the CRUD operations involved, there are some aspects to consider.

Create

URI: <server uri>/rest/<module>/<bc name>/<param1>,<param2>,..,<paramN>.

The parameters have to be sent in the body of the HTTP request. However, the Primary Key has to be sent in the URL.

The format of the URL is the same as in the GET method. The PK values have to be separated by commas.

<server uri>/rest/<module>/<bc name>/<param1>,<param2>,..,<paramN>

Example:

Method: POST 

URI: http://server/baseURL/rest/City/2

Body:
{
"CityName": "Rio de Janeiro",
"CityId": "2"
}

Return: Http code 201 

Body:
{
"CityName": "Rio de Janeiro",
"CityId": "2",
"gx_md5_hash": "24258169b5151be175ed72c92fd2c561"
}

HowTo: Insert data using a BC exposed as Rest service 

Read

URI: <server uri>/rest/<module>/<bc name>/<param1>,<param2>,..,<paramN>.

The PK values have to be separated by commas.

Example

Method: GET 

URI http://server/baseURL/rest/City/1

Return: Http code 200

{
"CityName": "Montevideo"
"CityId": "1"
"gx_md5_hash": "24258169b5151be175ed72c92fd2c561"
}

The body contains a hash value, needed for executing an UPDATE.

HowTo: Retrieve data from a BC exposed as a Rest service

Update

First get the data by its PK, using the HTTP GET verb and this generic URI:

<server uri>/rest/<module>/<bc name>/<param1>,<param2>,..,<paramN>.

Then update the data using the HTTP PUT verb. Similar to the POST, the PK parameters are included in the query string. The others in the body.

Example

Method: PUT 

After reading the gx_md5_hash using GET method : 

URI http://server/baseURL/rest/City/1

Body:

{
"CityName": "Roma",
"CityId": "1",
"gx_md5_hash": "24258169b5151be175ed72c92fd2c561"
}

Return: Http code 200

HowTo: Update data using a BC exposed as a Rest service

Delete

URI: <server uri>/rest/<module>/<bc name>/<param1>,<param2>,..,<paramN>.

Example

Method DELETE

URI : http://server/baseURL/rest/City/2

HowTo: Delete data from a BC exposed as a Rest service