Charles Guarino

Transcription

1 Looking Inside the Developer s Toolkit: REST Web Services for Everyday RPG and SQL Consumption Charles Guarino REST SERVICES Charles Guarino Central Park Data Systems, Inc. About The Speaker With an IT career spanning over 30 years, Charles Guarino has been a consultant for most of them. Since 1995 he has been founder and President of Central Park Data Systems, Inc., a New York area based IBM midrange consulting and corporate training company. In addition to being a professional speaker across the United States and Europe, he is a frequent contributor of technical and strategic articles and webcasts for the IT community. He is a member of COMMON s Speaker Excellence Hall of Fame and also Long Island Software and Technology Network s Twenty Top Techies. In 2015 Charles became the recipient of the Al Barsa Memorial Scholarship Award. Additionally, he serves as a member of COMMON s Strategic Education Team (SET) and is also a past president and monthly Q&A host of LISUG, a Long Island IBM i User s Group Charles can be reached at cguarino@centralparkdata.com. LinkedIn - Twitter Copyright Central Park Data Systems, Inc. 1

2 What We ll Cover Web services 101 XML versus JSON Real life web services XML using native SQL XML using native RPG JSON to XML using native RPG JSON to XML using native SQL Wrap-up How Do They Work? Local System Program A Program B PARAMETERS Consumer Provider Copyright Central Park Data Systems, Inc. 2

3 How Do They Work? The Cloud Power System running IBM I Program A Consumer Web Services Server on some other system Program B Provider More Web Services Fun Facts A STATELESS connection Can be sent in the clear or securely Can be public or private between companies or individuals Hardware, programming language and platform agnostic Can save you lots of $ -pre-written and tested and documented services Can be FREE, Restricted Access, Pay-For-Each-Use or Subscription Based Extends your applications in ways you may have never known possible, providing real time information. Can be many and simultaneous points of failure See the end of this presentation for useful links!!!! Copyright Central Park Data Systems, Inc. 3

4 Methods of Transport REST (Representational State Transfer) URL Web Services for the masses Copyright Central Park Data Systems, Inc. 4

5 How do they track your usage? But how do they make money? Copyright Central Park Data Systems, Inc. 5

6 What We ll Cover Web services 101 XML versus JSON Real life web services XML using native SQL XML using native RPG JSON to XML using native RPG JSON to XML using native SQL Wrap-up Data Format XML XML IBM ihas native parsing tools Extensible Markup Language Copyright Central Park Data Systems, Inc. 6

7 Data Format JSON JSON Java Script Object Notation What We ll Cover Web services 101 XML versus JSON Real life web services XML using native SQL XML using native RPG JSON to XML using native RPG JSON to XML using native SQL Wrap-up Copyright Central Park Data Systems, Inc. 7

8 Copyright Central Park Data Systems, Inc. 8

9 Copyright Central Park Data Systems, Inc. 9

10 Header Data First Day s Forecast Second Day s Forecast First screen prompts for zip code: Copyright Central Park Data Systems, Inc. 10

11 Subfile displayed with fully parsed data for zipcode 10038: What We ll Cover Web services 101 XML versus JSON Real life web services XML using native SQL XML using native RPG JSON to XML using native RPG JSON to XML using native SQL Wrap-up Copyright Central Park Data Systems, Inc. 11

12 Definitions For Using SQL and XML SYSTOOLS CCSID 37 CCSID CLOB versus BLOB XPATH A Review Once Again of the XML Data Header Data Starting point for SQL statement ForecastReturn/ForecastResult/Forecast First Day s Forecast Second Day s Forecast Copyright Central Park Data Systems, Inc. 12

13 HTTPGETCLOB!!! IBM i Navigator Using 7.1 Technology Refresh 6 Copyright Central Park Data Systems, Inc. 13

14 The NEW Power of the SQL Select Statement Select * from XMLTABLE(xmlnamespaces(default ' 'ForecastReturn/ForecastResult/Forecast' passing XMLPARSE(document( systools.httpgetclob(' tcityforecastbyzip?zip=10038',''))) Columns State VarChar(3) path '../../State', City VarChar(30) path '../../City', Station VarChar(30) path '../../WeatherStationCity', DateTime VarChar(50) path 'Date', Description VarChar(30) path 'Desciption', MorningLow VarChar(3) path 'Temperatures/MorningLow', DayTimeHigh VarChar(3) path 'Temperatures/DaytimeHigh', Nighttime VarChar(3) path 'ProbabilityOfPrecipiation/Nighttime', Daytime VarChar(3) path 'ProbabilityOfPrecipiation/Daytime')x; WEATHRRSQL Basic Program Flow Prompt for zip code Concatenate zip code and execute HTTPGETCLOB, place XML into variable BigVar Declare cursor, read 7 rows into data structure Load parsed data into subfile and display Copyright Central Park Data Systems, Inc. 14

15 Program WEATHRRSQL Stepping through the code, zip code was keyed. Copyright Central Park Data Systems, Inc. 15

16 Stepping through subprocedure ConsumeWebService Data structure XMLINDATA after SQL Fetch Copyright Central Park Data Systems, Inc. 16

17 Loading the subfile: What We ll Cover Web services 101 XML versus JSON Real life web services XML using native SQL XML using native RPG JSON to XML using native RPG JSON to XML using native SQL Wrap-up Copyright Central Park Data Systems, Inc. 17

18 WEATHRINTO Basic Program Flow Prompt for zip code Concatenate zip code and execute HTTPGETCLOB, place XML into variable BigVar Parse XML into data structures using RPG s XML-INTO Load parsed data into subfile and display Program WEATHRINTO Copyright Central Park Data Systems, Inc. 18

19 Header data A Closer Look Detail Data A Closer Look If you want to capture the data, the names must match misspellings and all! Copyright Central Park Data Systems, Inc. 19

20 Immediately after HTTPGETCLOB, loaded BigVar xml-into HeaderData: Copyright Central Park Data Systems, Inc. 20

21 Loaded data structure HeaderData: Loaded data structure WeatherData: Copyright Central Park Data Systems, Inc. 21

22 Loading the subfile: What We ll Cover Web services 101 XML versus JSON Real life web services XML using native SQL XML using native RPG JSON to XML using native RPG JSON to XML using native SQL Wrap-up Copyright Central Park Data Systems, Inc. 22

23 Sample API call using London, UK cca9337e1e96b00e0 Copyright Central Park Data Systems, Inc. 23

24 Copyright Central Park Data Systems, Inc. 24

25 API key stored in data area WEATHERMAP This is invalid XML data, needs to be fixed <1aaa> </1aaa> Copyright Central Park Data Systems, Inc. 25

26 WEATHRJSON Basic Program Flow Prepare URL from JSON web service, include app key from data area Execute HTTPGETCLOB, place JSON into Jsonstring place XML into variable BigVar Call program to convert JSON to XML Fix any bad XML tags Invoke XML SAX parser and write selected data elements to table WEBSVCDATA Program WEATHRJSON Copyright Central Park Data Systems, Inc. 26

27 Program call with parameter Costa Mesa, CA URL is loaded, appended with API key Copyright Central Park Data Systems, Inc. 27

28 Variable JSONSTRING Variable JSONSTRING converted to XMLSTRING Copyright Central Park Data Systems, Inc. 28

29 Parsed data in table WEBSVCDATA What We ll Cover Web services 101 XML versus JSON Real life web services XML using native SQL XML using native RPG JSON to XML using native RPG JSON to XML using native SQL Wrap-up Copyright Central Park Data Systems, Inc. 29

30 WTHRJSONXT Basic Program Flow Prepare URL from JSON web service, include app key from data area Execute HTTPGETCLOB, place JSON into Jsonstring place XML into variable BigVar Call program to convert JSON to XML Fix any bad XML tags Invoke XML SAX parser and INSERT rows from selected data elements to table WEATHERDATA Program WTHRJSONXT Copyright Central Park Data Systems, Inc. 30

31 JSONSTRING is loaded from web service XMLSTRING is loaded from web service Copyright Central Park Data Systems, Inc. 31

32 At the beginning of subprocedure processxml Insert row into table WeatherData Copyright Central Park Data Systems, Inc. 32

33 Table WeatherData(Weath00001) after insert What We ll Cover Web services 101 XML versus JSON Real life web services XML using native SQL XML using native RPG JSON to XML using native RPG JSON to XML using native SQL Wrap-up Copyright Central Park Data Systems, Inc. 33

34 Looking Inside the Developer s Toolkit: REST Web Services for Everyday RPG and SQL Consumption Charles Guarino REST SERVICES Charles Guarino THANK YOU!!! Definitions XML (extensible Markup Language) Unlike HTML which has pre-defined tags, the tags can have any value you wish. This is what makes it extensible. Your document must still be well-formed to be parsed, meaning each start tag must have a corresponding end tag. The actual data is stored between the tags. Parsing The shredding or extraction of the XML data from its tags. SOAP Simple Object Access Protocol Message-based, you create a message similar to an using a pre-defined language, Web Services Definition Language, or WSDL ( wiz-dul ). Copyright Central Park Data Systems, Inc. 34

35 Definitions (cont.) REST (Representation State Transfer) HTTP based, no need to create a message Web service can be consumed using a browser U.R.I. (Universal Resource Identifier) More broadly based than a URL, which refers to a website, is used to identify any object in the cloud Helpful resources The basics of RESTful web services y/ws-restful XML Name Spaces SQL Messages and Codes When Using SQL With DB2 for i sp?topic=%2frzala%2frzalakickoff.htm Copyright Central Park Data Systems, Inc. 35

36 Helpful resources A good primer on understanding CCSID story03.html A beginner s definition of BLOB A beginner s definition of CLOB Helpful resources What is SYSTOOLS? sp?topic=%2frzajq%2frzajqsystools.htm IBM developerworks website discussing new SQL HTTP functions, including HTTPGETCLOB home?lang=en#!/wiki/ibm%20i%20technology%20updat es/page/new%20http%20functions%20added%20to%20 SYSTOOLS A beginner s tutorial on XPATH Copyright Central Park Data Systems, Inc. 36

37 Additional Session Information To Run SQL Scripts in IBM inavigator Open your connection in Navigator Open Databases When your database name appears, right click on it. In the menu, click on Run SQL Scripts When you are in the SQL Scripts window, click on Connection and select Temporary JDBC Settings In the Translation tab, make sure Translate CCSID is CHECKED. Software Disclaimer DISCLAIMER OF WARRANTIES AND LIMITATION OF LIABILITY The software is supplied as is and all use is at your own risk. Central Park Data Systems Inc. and/or Charles Guarino disclaims all warranties of any kind, either express or implied, as to the software, including, but not limited to, implied warranties of fitness for a particular purpose, merchantability or non infringement of proprietary rights. No documentation furnished is intended to express or imply any warranty that the operation of the software will be uninterrupted, timely, or error free. Copyright Central Park Data Systems, Inc. 37