Transcript XML Over The Web Today

XML Over The
Web Today
Dino Esposito
Wrox Press
6-313
Agenda
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Present and future of XML and HTTP
XmlHttpRequest
Using XmlHttpRequest in
Visual C++® apps
Architecturally speaking…
Why XML
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Text-based and human-authorable
Available on (almost) all platforms
Great for describing data
Designed to be simple and effective
Why HTTP
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Broadly accepted
Jumps through firewalls
Designed to be simple but effective
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No runtime support unlike DCOM
Why XML And HTTP
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Another (better?) component model
Increase interoperability
No mandated API or runtime
Industry standards
The World Without XML
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HTML and ASP
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Remote data services
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Server-side pages
COM calls through HTTP
Remote scripting
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ECMAScript calls through HTTP
The World Without HTTP
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DCOM
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COM Internet services
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Complexity and dynamic ports
DCOM over HTTP via tunneling TCP
Internet InterORB protocol
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Protocol to connect different ORBs
The World With XML+HTTP
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Connect to remote services
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Platform and language neutrality
Send and receive XML text
Get the best of both worlds
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Encoding and data representation
Connect to a Linux CGI from Visual Basic®!
SOAP Breaks In
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Services over the network
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Connect through HTTP
Communicate through XML
An XML-based language for remote
method invocation
Open specification with trial
implementations
Doesn’t reinvent any wheel
Agenda
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Present and future of XML and HTTP
XmlHttpRequest
Using XmlHttpRequest in
Visual C++ apps
Architecturally speaking…
XmlHttpRequest?
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Part of MSXML (Microsoft.XMLHTTP)
Arbitrary HTTP requests and responses
Does not use SOAP (yet?)
XmlHttpRequest And SOAP
Web Service
XmlHttpRequest
URL
Web Service
SOAP Request
SOAP Response
XMLDOM
Client
COM-based client
How It Works
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Create an instance of the object
Set operation and URL
Send data
Get the response
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Raw text, XMLDOM, IStream, array
A XMLHTTP Request
Set xmlhttp = CreateObject("Microsoft.XMLHTTP")
xmlhttp.open "GET", “http://expoware/demo/test.asp",
false
xmltext = "<magazine>MSDN</magazine>"
Set xmldom = CreateObject("Microsoft.XMLDOM")
xmldom.loadXML xmltext
xmlhttp.send xmldom
A XMLHTTP Response
<%
set xmldom = Server.CreateObject("Microsoft.XMLDOM")
xmldom.load(Request)
set n = xmldom.selectSingleNode("magazine")
n.text = “MSDN Magazine"
strText = “New text is: " & xmldom.xml
Response.Write strText
%>
Methods And Properties
Description
Method/Property
open
M
Sets the params for the conversation
send
M
Sends data through HTTP
abort
M
Cancels the current operation
readyState
P
Readiness of the object
responseText
P
Response as raw text
responseXML
P
Response as XMLDOM
responseBody
P
Response as an array of bytes
Agenda
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Present and future of XML and HTTP
XmlHttpRequest
Using XmlHttpRequest in
Visual C++ apps
Architecturally speaking…
Example #1
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C++ application that utilizes
the component
XmlHttpRequest
Example #2
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MFC application that fills its own UI with
XML data taken from an ASP page
XmlHttpRequest
XmlHttpRequest
Exchanging XMLDOM
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Use send to pass an XMLDOM
Target ASP pages process it
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xml.loadXML(Request)
ASP page returns XML text
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Set ContentType to text/xml
Use responseXML to retrieve it
Agenda
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Present and future of XML and HTTP
XmlHttpRequest
Using XmlHttpRequest in
Visual C++ apps
Architecturally speaking…
Web Services
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Any service available on the Web
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Components, applications, servers, pages
Platform and language neutrality
Web services versus DCOM
New Web Apps
Web client
Components
Win32 client
Web Server
Other platform
client
Operating
System
Any platform!
Data
Store