[SAP HANA Academy] Live3: Web Service - Setup XSJS

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[Update: April 5th, 2016 -  The Live3 on HCP tutorial series was created using the SAP HANA Cloud Platform free developer trial landscape in January 2015. The HCP landscape has significantly evolved over the past year. Therefore one may encounter many issues while following along with the series using the most recent version of the free developer trail edition of HCP.]

Part of the SAP HANA Academy’s Live3 on HCP course, the below video tutorial from philip.mugglestone shows how to add server-side scripting capabilities to the live3 web services project. With this you can configure actions to refresh the clustering and reset the database. Watch Philip’s video below.

(0:35 – 3:00) Inserting the Proper Schema Name and P Number into the services.xsjs Code

With the live3 project selected in the SAP Web-based Development Workbench, open the services folder of the Live3 GitHub code repository and drag the services.xsjs file in the Multi-File Drop Zone. First you must do a global replace to insert your schema name. Also you must insert your account p number where marked in the code as the code checks to verify if the user has the execute privilege. After verification the user can preform the reset and/or cluster operation.

(3:00 – 6:00) Examining the Code’s Logic

The code is very straight forward. It first checks if the user has the privilege to execute. If so then the URL command (cmd) parameter will be returned. It will pause there and wait for the command. If cmd=reset then it will call the reset function and if cmd=cluster than it will call the cluster function. If neither reset nor cluster is entered then it will display invalid command. If the user isn’t authorized then a not authorized message will appear.

The reset function’s code first sets the schema and then truncates (empties) the Tweets table that is loaded directly via node.js. Next it empties the PAL results and centers tables. Then the full text analysis index is first cleaned out and then recreated using the same code that was used earlier in the setup text analysis piece. The only difference from earlier is that the code is modified with a backslash in front of every single quotation mark in the SQL.

The cluster function’s code is similar to the setup Predictive SQL code. The schema is set and the PAL results and centers tables are truncated. Then the procedure is called. On the web as opposed to seeing the results directly, instead the results table will display questions marks first. Then it will loop around a set of results and then insert those results into the table using JavaScript.

(6:00 – 7:30) Testing services.xsjs

Executing the services.xsjs file will open a web page that displays invalid command: undefined. This should happen as it didn’t recognize the default command that was specified. So you must delete the default anti caching system that appears after /service.xsjs? in the URL and them add a valid command. For instance cmd=cluster.

Entering the command for cluster won’t display anything on the web page at this point. However to show that the file has run with a valid command open the developer tools (control+shift+I in Chorme) and go to the network tab. In the network tab there will be information about the call.

Follow along with the Live3 on HCP course here.

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