Getting the Most from REST and JSON

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Melinda Caldwell
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1 Getting the Mst frm REST and JSON Jhn Tuhy March 2018

2 Character encding review Single byte character encding ASCII OEM ANSI Multi-byte character encding (Unicde) UTF-16 UTF-8 DataFlex des mst f its character (string) prcessing in OEM The standard character exchange ver the Internet is UTF-8

3 The HTTP transfer prtcl Different types f HTTP requests use different t prtcls The mst cmmn are Pst and Get There are thers such as Put, Delete and Patch - these are referred t as verbs The lw level http interface actually has yu send these verbs as: GET, POST, PATCH, PUT, DELETE Basically a request sends a verb and data with sme header infrmatin Until early 2000s the HTTP verbs were cnsidered lw-level arcane knwledge

4 REST Then REST and RESTful web-services were created REST: Representatinal state transfer (REST) r RESTful Web services are ne way f prviding interperability between cmputer systems n the Internet. REST-cmpliant Web services allw requesting systems t access and manipulate textual representatins f Web resurces using a unifrm and predefined set f stateless peratins. (Wikipedia)

5 REST web services REST uses three parts f an HTTP request t create web-service Verb URL Data Verb the verb t define the peratin GET used t retrieve data DELETE use t delete data POST Used t Create data PUT Used t Replace data PATCH is used t. whatever URL - It uses the URL t determine what the peratin is acting n //api.example.cm/custmers/ //api.example.cm/custmers/1 //api.example.cm/custmers/1/rders Data is passed and returned as HTTP data

6 REST web services (cntinued) T make this all a bit mre cncrete: REST uses the standard HTTP verbs and URLs t determine what t d The data is exchanged as HTTP character data REST ften exchanges data in JSON REST transfers the JSON data using UTF-8 The cntent f the data is whatever the service defines ( and yu need t figure this ut) SOAP web service vs. Rest web service Nt at all the same thing

7 The DataFlex HTTP transfer classes chttptransfer Lw level Supprts the mst cmmn HTTP transfer verbs: Get, Pst (and Put) Get HttpGetRequest Get HttpPstRequest Get HttpPstAddrRequest As f 18.2, it supprts any http verb Get HttpVerbAddressRequest Returns the data in an event, its yur jb t prcess it Prcedure OnDataReceived Yu can send and receive in whatever encding frmat yu want (i.e., it s yur prblem) cxmlhttptransfer Sub-class f chttptransfer Used t transfer XML data acrss requests Passes and receives XML bjects, if invalid XML, it fails Supprt HTTP Pst and Get Get HttpGetXmlNde Get HttpPstXmlNde Uses UTF8 encding Used by client web-services (cclientwebservice), which is why yu never see it.

8 cjsnhttptransfer class Sub-class f chttptransfer Used t transfer JSON data acrss requests Passes and receives JSON bjects, if invalid JSON data, it fails Supprts all RESTful verbs Get, Pst, Put, Delete, Patch and "verb" just in case Get HttpGetJsn Get HttpPutJsn Get HttpPstJsn Get HttpPatchJsn Get HttpDeleteJsn Get HttpVerbJsn Uses UTF8 encding Used t transfer JSON via Http - yu have t write the cde yurself

9 Using cjsnhttptransfer bjects Object JsnHttp is a cjsnhttptransfer End_Object Get HttpGetJsn f JsnHttp "api.example.cm" "custmers" (&bok) t hjsnout Get HttpGetJsn f JsnHttp "api.example.cm" "custmers/1" (&bok) t hjsnout Get HttpGetJsn f JsnHttp "api.example.cm" "custmers/1/orders" (&bok) t hjsnout Get HttpPstJsn f JsnHttp "api.example.cm" "custmers" hjsonin (&bok) t hjsnout Get HttpPatchJsn f JsnHttp "api.example.cm" "custmers/1" hjsonin (&bok) t hjsnout Get HttpDeleteJsn f JsnHttp "api.example.cm" "custmers/1" 0 (&bok) t hjsnout

10 Examples Fr the samples we use:

cloud services access to everything over the web

cloud services access to everything over the web clud services access t everything ver the web Disclaimer: This dcument is prvided as-is. Infrmatin and views expressed in this dcument, including URL and ther Internet Web site references, may change withut