PHP talking to SAP

1
PHP talking to SAP

• Martin Probst

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PHP / Outline

• demo of leave request
• desktop integration via Atom iCalendar
• consuming web services in PHP
• feedback (technical, documentation, missing
  functionality)

3
demo
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PHP / consuming web services /iCalendar Atom

• Web interfaces are location independent,
  lightweight etc.
• But users prefer rich clients sometimes
• Better interface
• Integrate with other tools
• Aggregate data from many sources
• Support open iCalendar and Atom formats
• easy to produce and consume
• wide range of applications
• open standards (RFCs)
• Implementation read only, but not necessarily
  (WebCAL, APP)

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PHP / consuming web services /the basic code

• No real type system
• Create SOAP client, dynamic methods on it added
• Everything done at run time, but cached

wsdl 'http//www.sap.com/.../ECC_EMPLEAVEREQBYI
DQR.wsdl' soapclient new SoapClient(wsdl) m
essage array ( 'EmployeeLeaveRequestSelectionBy
ID' gt array ( 'EmployeeLeaveRequestID' gt
ID ) ) response soapclient-gt EmployeeLeaveR
equestByIDQueryResponse_In(message)
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PHP / consuming web services /dynamic types

• PHP has a dynamic (or no?) type system
• Classes are constructed from WSDL/Schema on the
  fly
• Can supply user implemented classes
• Use hash maps/arrays to construct messages
• Consume result types directly, no declaration
• This is all the code necessary to query services
• minimal LOC, but no static type check

leaverequest response-gtEmployeeLeaveRequest e
cho leaverequest-gtLifeCycleStatusCode,
leaverequest-gtStartDate
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PHP / consuming web services /problems

• Automatic type conversion error proneis it a
  number, a string, a bird?
• Unstable language
• 5.1 ? 5.2 _toString semantics change, Datetime
  class added
• backwards incompatible changes, break code
• Object oriented system strange at best
• Field visibility not enforced
• Types sometimes case insensitive

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PHP / consuming web services /soap issues

• SOAP API added in PHP5
• Hash map syntax for messages? no support for
  namespaces in messages
• Serialization into XML overly liberal
• fails to detect many bugs
• easy to send non-WSDL-conforming messages
• Fehler bei der Konvertierung XML gt ABAP (
  FehlerId ( ) )

message array ( 'EmployeeLeaveRequestSelection
ByID' gt array ( 'EmployeeLeaveRequestID' gt
ID ) )
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PHP / consuming web services /soap issues

• Arrays weird - if its only one element, its not
  an array? need special case code everywhere
• Difficult to manage types in non typed system
• EmployeeLeaveRequest type different in services
• PHP has no way to handle this
• Create messages as hashmaps for each request

elr res-gtEmployeeLeaveRequest if
(is_array(elr)) elr array (elr)
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conclusion

• PHP
• small server footprint
• low complexity (2000 LOC, zipped 60KB)
• quick development cycle
• bad programming language
• rather go for Ruby / Python
• Services
• see other feedback
• last modified for service would be nice