Looking Inside the Developer s Toolkit: Web Services for Everyday RPG Consumption. Charles Guarino XML. Charles Guarino

Transcription

1 Looking Inside the Developer s Toolkit: Web Services for Everyday RPG Consumption Charles Guarino XML Charles Guarino Central Park Data Systems, Inc. Copyright Central Park Data Systems, Inc. 1 About the Presenter: With an IT career spanning over 25 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 Long Island based IBM midrange consulting company. He has published several technical and strategic articles for the IT community and has served as a member of a technical publication s Editorial Review Board. He was inducted into COMMON s Speaker Excellence Hall of Fame in 2008 and also selected as one of LISTnet's Long Island s Twenty Top Techies for Charles is currently a COMMON Application Development Subject Matter Expert and a Board Member and monthly Q&A host of LISUG, a Long Island IBM System i User s Group. Charles can be reached at cguarino@centralparkdata.com. 1

2 In This Session. Web services extend your applications by providing functionality you should not or could not write yourself. We will demonstrate what a web service is, where to find them and how to consume them. We will explore how supplying just a zip code to an application can return meaningful and real time information that is well beyond your company s four walls. All of the source code for these programs can be downloaded and compiled on your own systems and be put to use immediately. They are production ready! Copyright Central Park Data Systems, Inc. 3 What We ll Cover Definitions and Prerequisites Introduction to Web Services Weather Forecast by Zip Code Traffic Conditions by Zip Code Wrap Up Copyright Central Park Data Systems, Inc. 4 2

3 Definitions see the appendix! XML (extensible Markup Language) Parsing Web Service SOAP (Simple Object Access Protocol) WSDL (Web Service Definition Language) REST (Representational State Transfer) URI (Uniform Resource Identifier) HTTPAPI (Hypertext Transfer Protocol API) Copyright Central Park Data Systems, Inc. 5 PREREQUISITES 1) RPGLE, i5 OS Version 5.4 or higher 2) Knowledge of how to navigate in the IFS 3) Familiarity with nested data structures, and how they re represented on d specs 4) Basic knowledge of XML or HTML Copyright Central Park Data Systems, Inc. 6 3

4 What We ll Cover Definitions and prerequisites Introduction to web services Weather Forecast by Zip Code Traffic Conditions by Zip Code Wrap Up Copyright Central Park Data Systems, Inc. 7 Simplistic diagram of a web service request Internet System i Some other system Copyright Central Park Data Systems, Inc. 8 4

5 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 The Great Online Battle!!! SOAP REST SOAP Simple Object Access Protocol REST Representational State Transfer Copyright Central Park Data Systems, Inc. 10 5

6 Where can I find free web services? The Internet, of course!!! What We ll Cover Definitions and prerequisites Introduction to web services Weather Forecast by Zip Code Traffic Conditions by Zip Code Wrap Up Copyright Central Park Data Systems, Inc. 12 6

7 Zip Code Anatomy Fun Facts The first digit indicates a general geographic area of the nation, starting with 0 in the eastern U.S. to 9 representing areas in the western U.S. The next two numbers represent regional areas. The final two identify specific post offices or postal zones. The Plus 4 code identifies a geographic segment within the five-digit code, such as a city block, a group of apartments or any other individual high-volume receiver of mail that can aid more efficient mail sorting and delivery. Copyright Central Park Data Systems, Inc. 14 7

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9 Header Data First Day s Forecast Second Day s Forecast Copyright Central Park Data Systems, Inc. 17 We ve selected a web service (CDYNE s Weather Forecast by Zip Code) Next we need a way to communicate with the Web, to handle the plumbing. FREE SOFTWARE!!! Visit Copyright Central Park Data Systems, Inc. 18 9

10 First screen with simple error message shown: Copyright Central Park Data Systems, Inc. 19 When an invalid zip code is keyed, display second error message: Copyright Central Park Data Systems, Inc

11 Subfile displayed with fully parsed data for zipcode 10038: Copyright Central Park Data Systems, Inc. 21 Start of program, request zip code from user If EOJ (F3) requested, RETURN Zip code cannot be *zeros, if so re-display screen Build URI Create XML document name for placement in /tmp in IFS Retrieve data from web service using HTTPAPI Parse header data Was valid data received? (does Success = True?) Parse remaining detail data Load and display subfile Return to start 22 11

12 RPGLE Program WEATHERSCN Copyright Central Park Data Systems, Inc. 23 Header data A Closer Look Copyright Central Park Data Systems, Inc

13 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. 25 A Quick Tribute to Mr. Zip, a.k.a. Zippy Adopted on July 1 st, 1963 by the Post Office Department as the trademark of the ZIP (Zoning Improvement Plan) Code Source: 13

14 Running program WEATHERSCN using RDP debug perspective XML Data in document QACX1WMAR0.xml. Header and Detail data shown. 14

15 Immediately following XML-INTO statement, DS HEADERDATA is populated Immediately following XML-INTO statement, DS WEATHERDATA is populated 15

16 Loop through, load subfile and then display What We ll Cover Definitions and prerequisites Introduction to web services Weather Forecast by Zip Code Traffic Conditions by Zip Code Wrap Up Copyright Central Park Data Systems, Inc

17 A real life example to using a web service in an application HELP!!! I have an EMERGENCY!!! What is your ADDRESS? * We re sending help RIGHT NOW! We ll provide REAL-TIME traffic conditions to give the driver the best route!!! * We ll use Zip Code instead for privacy protection Copyright Central Park Data Systems, Inc offers free geographic web services Copyright Central Park Data Systems, Inc

18 A sampling of GeoNames web services. We will select postalcodesearch Copyright Central Park Data Systems, Inc. 35 GeoNames Postal Code Search Documentation Copyright Central Park Data Systems, Inc

19 This web service shows any postal code in the world with Copyright Central Park Data Systems, Inc Shown here with optional country filter Copyright Central Park Data Systems, Inc

20 Googled Mapquest Web Services or Copyright Central Park Data Systems, Inc. 39 Link to Mapquest Parameters explains how to use this service in a browser, including all optional parameters Need to compose a URL as follows, replacing longitude and latitude : Copyright Central Park Data Systems, Inc

21 Header Data Detail Data Copyright Central Park Data Systems, Inc. 41 Prompt the user for the zip code Copyright Central Park Data Systems, Inc 42 21

22 Entering all zeros displays an error message Copyright Central Park Data Systems, Inc 43 Display an error message when an invalid zip code is entered Copyright Central Park Data Systems, Inc 44 22

23 When a valid zip code is entered, launch a browser and position on coordinates Copyright Central Park Data Systems, Inc. 45 Start of program, request zip code from user If EOJ (F3) requested, RETURN Zip code cannot be *zeros, if so re-display screen Build URI Get filename for placement in /tmp in IFS Retrieve data from web service using HTTPAPI Parse header data Was valid data received? (was a valid U.S. location returned?) Parse remaining detail data Pass coordinates to CLLE browser display program Return to start Copyright Central Park Data Systems, Inc

24 RPGLE Program ZIPCODELOC Copyright Central Park Data Systems, Inc. 47 Parse Header data Copyright Central Park Data Systems, Inc. 24

25 Parse Detail Data Copyright Central Park Data Systems, Inc. 49 CLLE that launches web browser Where the real magic happens Copyright Central Park Data Systems, Inc

26 In case you have a very long URL Search for STRPCCMD PCCMD Request zip code from user: Copyright Central Park Data Systems, Inc

27 Compose the URI: Copyright Central Park Data Systems, Inc. 53 Generate random file name to hold data in the IFS. The name will be different every time you run the program. Copyright Central Park Data Systems, Inc

28 Captured data in IFS file Note the same file name QACXLR4Z1.xml Copyright Central Park Data Systems, Inc. 55 Parse the header data. This is the variable view of HeaderData. Copyright Central Park Data Systems, Inc

29 Parse the detail data Copyright Central Park Data Systems, Inc. 57 CL program ZIPCODECL receives the latitude and longitude, builds the URL in field name &URL and opens a browser. Copyright Central Park Data Systems, Inc

30 Launch browser and position map at coordinates Copyright Central Park Data Systems, Inc. 59 What We ll Cover Definitions and prerequisites Introduction to web services Weather Forecast by Zip Code Traffic Conditions by Zip Code Wrap Up Copyright Central Park Data Systems, Inc

31 Looking Inside the Developer s Toolkit: Web Services for Everyday RPG Consumption Charles Guarino XML Charles Guarino THANK YOU!!!! Copyright Central Park Data Systems, Inc. 61 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 ripping apart 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 62 31

32 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 HTTPAPI Software used on the Power System which allows the system to connect and consume a web service Visit a free download Can basically be considered a batch browser Copyright Central Park Data Systems, Inc 63 32