Syed Hussim - Software development

Introduction To Node.js 29 May 2019 - 5 views
I've been developing alot of Node.js applications lately and though I might start a new category on this blog with articles on Node.js.

Node.js is an asynchronous event driven JavaScript runtime built on Chrome's V8 JavaScript engine. It is deisnged to build scalable networking applications but can also be used to develop applications with GUI's using thrid party libraries. The Node Package Manager (npm) allows you to install third party packages either from the npm repository or install a local package from your computer.
Getting Started

Node.js is extremly simple to install on all OS platforms. On Windows there is an installer, which guides you through the setup process. For Ubuntu users simply type the following command.

sudo apt-get install nodejs
Once the process has completed, you can verify, if Node.js is installed correctly by typing the following command.

nodejs --version
Node Packager Manager (npm) is installed by default when you install Node.js. You can verify if npm is installed by typing the following command.

npm --version
Now that Node.js is installed, you can write your first program. Open a text editor and write the famous Hello World program. Save the file as app.js.
Listing 1
1. 1console.log("Hello World");
To execute the code, cd into the directory where app.js is located in a terminal or command prompt and type the following command.

nodejs app.js
You should now see Hello World prinited to the terminal. This example doesnt demonstrate a lot but in the next few articles you'll become to relaise just how powerful Node.js is.
Connect To HANA DB Using Python 11 October 2018 - 895 views
This article explains how to connect to a SAP HANA system using the Python hdbcli package. The package is available as part of the SAP HANA HDB client software. The client software can be downloaded when installing HANA Express.
Once the client software is installed, locate the file hdbcli-x-y-z.tar.gz. The next step is to install the Python hdbcli package. This can be done easily using the Python utility program pip. Execute the following command in a terminal.

pip install /path/to/hdbcli-x-y-z.tar.gz
After the process completes, the Python hdbcli package will be installed. Listing 1 below shows a simple script that tests the database connection.
Listing 1
1. 1from hdbcli import dbapi
2. 2
3. 3connection = dbapi.connect('SERVER_HOST', PORT_NUMBER, 'USERNAME', 'PASSWORD')
4. 4
5. 5print(connection.isconnected())
Replace the connect arguments to reflect your own systems credentials. The SERVER_HOST can be an IP address or a host name.

The script will print True when a successful connection is made.

Executing Queries

SQL statements are executed on a Cursor object. Listing 2 below shows a simple SQL statement that returns the current date.
Listing 2
1. 1...
2. 2cursor = connection.cursor()
3. 3
4. 4cursor.execute('SELECT NOW() FROM DUMMY')
5. 5
6. 6row = cursor.fetchone()
7. 7
8. 8print(row[0])
Notice on line 2, the cursor() method is used to return a Cursor object. This object is then used to execute SQL statements.

The execute() method returns a Boolean value indicating if the statement executed successfully. The Cursor object exposes several methods to return data. The fetchone() method is used to return a single row while fetchall() returns multiple rows.
Adding Auto Numbers To Table Columns 14 March 2018 - 1074 views
As of SPS8, SAP introduced the ability to create auto generated columns that increment by using IDENTITY. Auto generated columns only apply to Column table types. To create an auto generated column, simply add GENERATED BY DEFAULT AS IDENTITY to the column as shown in Listing 1 below.
Listing 1
1. 1CREATE COLUMN TABLE Employee(
2. 2 EMPLOYEE_ID BIGINT GENERATED BY DEFAULT AS IDENTITY,
3. 3 FIRST_NAME VARCHAR(30),
4. 4 LAST_NAME VARCHAR(30)
5. 5)
If you need to start the identity value from a particular number, you can add START WITH 1000 as an argument to IDENTITY where 1000 is the value to start from.
Listing 2
1. 1 ...
2. 2 EMPLOYEE_ID BIGINT GENERATED BY DEFAULT AS IDENTITY(START WITH 1000),
3. 3 ...
The identity value increments by 1 when data is inserted into the table but this can be changed using INCREMENT BY 2 where 2 is the value to increment by.
Listing 3
1. 1 ...
2. 2 EMPLOYEE_ID BIGINT GENERATED BY DEFAULT AS IDENTITY(START WITH 1000 INCREMENT BY 2),
3. 3 ...
PHP Service Layer Example Part 2 25 January 2018 - 1863 views
This article is part 2 of PHP Service Layer Example. In the previous article, I explained how to initiate an authentication request to get a Service Layer session id and route id. In this article we use these details to execute a request to retrieve a list of business partners.
To follow along with this article, I would suggest reading my previous article PHP Service Layer Example Part 1.

The B1SESSION and ROUTEID must be sent as cookies in the request header for subsequent requests. Using the curl_setopt() function, you can set the request header as shown in Listing 1 below.
Listing 1
1. 1...
2. 2
3. 3$sessionId = "8daf55f4-01bf-11e8-8000-002655851f48";
4. 4$routeId = ".node0";
5. 5$headers[] = "Cookie: B1SESSION=" . $sessionId . "; ROUTEID=" . $routeId . ";";
6. 6
7. 7curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
Listing Business Partners

To get a list of Business Partners, you need to call the /b1s/v1/BusinessPartners resource URI. As this resource returns data, you must use the HTTP GET request method. Listing 2 below shows a complete code sample, that returns all business partners.
Listing 2
1. 1$host = "";
2. 2$port = 50000;
3. 3
4. 4$sessionId = "3d78cc04-01c5-11e8-8000-002655851f48";
5. 5$routeId = ".node2";
6. 6$headers[] = "Cookie: B1SESSION=" . $sessionId . "; ROUTEID=" . $routeId . ";";
7. 7
8. 8$curl = curl_init();
9. 9curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
10. 10curl_setopt($curl, CURLOPT_URL, $host . ":" . $port . "/b1s/v1/BusinessPartners");
11. 11curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
12. 12curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
13. 13
14. 14$response = curl_exec($curl);
15. 15
16. 16echo $response;
A successful request will return an HTTP 200 OK status with a JSON response. If the B1SESSION is invalid, an HTTP 401 Unauthorized is returned along with the following JSON response.
Listing 3
1. 1{
2. 2 "error" : {
3. 3 "code" : 301,
4. 4 "message" : {
5. 5 "lang" : "en-us",
6. 6 "value" : "Invalid session."
7. 7 }
8. 8 }
9. 9}
Selecting Properties And Applying Filters

By default, all properties relating to a business partner is returned resulting in a huge amount of data being transfered. This can have performance issues, most especially when you have a lot of business partners.

Thankfully as the Service Layer uses the oData protocol, you can query the BusinessPartners resource to return properties that are of interest to you thereby reducing the data being transfered. Listing 4 below shows how to return business partners with selected properties.
Listing 4
1. 1...
2. 2$select = '?$select=CardCode,CardName,CardType,Address,City,Country,ZipCode';
3. 3...
4. 4curl_setopt($curl, CURLOPT_URL, $host . ":" . $port . "/b1s/v1/BusinessPartners" . $select);
Additionally, you can filter the result by apply a filter option to the query. Listing 5 below shows how to return business partners where the CardCode property starts with 'A'.
Listing 5
1. 1...
2. 2$select = '?$select=CardCode,CardName,CardType,Address,City,Country,ZipCode';
3. 3$filter = '&$filter=' . rawurlencode("startswith(CardCode, 'A')");
4. 4...
5. 5curl_setopt($curl, CURLOPT_URL, $host . ":" . $port . "/b1s/v1/BusinessPartners" . $select . $filter);
It is important to remember that you must escape the query where appropriate. Failure to do so will result in a bad request. The oData protocol provides a range of operators and functions to query data. Consult the oData documentation for further details.
PHP Service Layer Example Part 1 09 January 2018 - 2124 views
SAP Business One provides a REST Service Layer API which can be used to consume data and services. In this article, I explain how to use PHP to communicate with the Service Layer. Before getting started, ensure that you have the PHP CURL library installed and configured. If you are unfamiliar with the Service Layer, you should read my previous article Introduction To SAP Business One Service Layer.
Authentication

Like many API's the Service Layer requires authentication using a SAP user account. A successful login, will return a JSON string that contains a session id and the response header will contain a ROUTEID in the cookie header. Both the session id and the ROUTEID should be used in subsequent requests. Listing 1 below shows how to initiate the authentication process.
Listing 1
1. 1// Host name
2. 2$host = "";
3. 3
4. 4// Port
5. 5$port = 50000;
6. 6
7. 7// Login credentials
8. 8$params = [
9. 9 "UserName" => "",
10. 10 "Password" => "",
11. 11 "CompanyDB" => "",
12. 12];
13. 13
14. 14$curl = curl_init();
15. 15curl_setopt($curl, CURLOPT_URL, $host . ":" . $port . "/b1s/v1/Login");
16. 16curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
17. 17curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
18. 18curl_setopt($curl, CURLOPT_VERBOSE, 1);
19. 19curl_setopt($curl, CURLOPT_POST, true);
20. 20curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($params));
21. 21
22. 22$response = curl_exec($curl);
Notice that the request is made to "/b1s/v1/Login". This is the authentication URI, which requires a SAP user login credential and the database to connect to. Post data should be JSON encoded as seen on line 20.

If the request is authorized, a JSON response similar to Listing 2 below is returned.
Listing 2
1. 1{
2. 2 "odata.metadata" : "host:port/b1s/v1/$metadata#B1Sessions/@Element",
3. 3 "SessionId" : "0dacaec2-f5fa-11e7-8000-002655851f48",
4. 4 "Version" : "920200",
5. 5 "SessionTimeout" : 30
6. 6}
The JSON response above contains the SessionId property, which is required in subsequent requests along with the ROUTEID. The ROUTEID is not returned in the JSON response. It is set in the response Cookie header. Using some basic string manipulation, the ROUTEID can be extracted from the response Cookie header as shown in Listing 3 below.
Listing 3
1. 1...
2. 2
3. 3$routeId = "";
4. 4
5. 5curl_setopt($curl, CURLOPT_HEADERFUNCTION, function($curl, $string) use (&$routeId){
6. 6 $len = strlen($string);
7. 7
8. 8 if(substr($string, 0, 10) == "Set-Cookie"){
9. 9 preg_match("/ROUTEID=(.+);/", $string, $match);
10. 10
11. 11 if(count($match) == 2){
12. 12 $routeId = $match[1];
13. 13 }
14. 14 }
15. 15 return $len;
16. 16});
17. 17
18. 18curl_exec($curl);
19. 19
20. 20echo $routeId;
The curl CURLOPT_HEADERFUNCTION constant is used to provide a callback function that is called for each header in the response. This callback function is used to determine if the header is Set-Cookie and if it is, then extract the value for the ROUTEID cookie using the preg_match function. It is also worth mentioning that the SessionId returned as part of the JSON response is also sent as a cookie header. You can extract both the SessionId and ROUTEID from the response Cookies. Note; that the cookie name for SessionId in the response header is B1SESSION and not SessionId.

In part 2, PHP Service Layer Example Part 2, I explain how to use the SessionId and ROUTEID to get a list of business partners.

SYEDHUSSIM.COM

Getting Started

Listing 1

Listing 1

Executing Queries

Listing 2

Listing 1

Listing 2

Listing 3

Listing 1

Listing Business Partners

Listing 2

Listing 3

Selecting Properties And Applying Filters

Listing 4

Listing 5

Authentication

Listing 1

Listing 2

Listing 3