SAS 917: Web Services with Adaptive Server Anywhere

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SAS 917 Web Services with Adaptive Server
Anywhere
John Poole Software Developer, iAnywhere
Solutions jpoole_at_ianywhere.com August 6, 2003
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Agenda

• Introduction to Web Services
• Thirty Second Web Service
• WeatherData Web Service
• Server Switch
• Web Service Statements
• Web Service Types
• Server Addressing
• Service Determination
• Parameter Handling
• Functions and System Functions

3
Introduction to Web Services

• What is a web service?
• A web service is a programmatic interface that is
  used for application-to-application communication
  over a network. Web services use widely-used
  technologies and standards such as XML and HTTP
  in order to make these interfaces platform and
  language independent.
• How does Banff support web services?
• Banff includes an embedded HTTP server, which
  allows developers to create and deploy web
  services directly from the database.
• Web services in Banff support a number of
  different technologies and standards, including
  HTTP, XML, SOAP, and WSDL.

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Thirty Second Web Service

• From the command line
• dbinit web.db
• dbeng9 -xs http web.db
• From dbisql
• create service tables type xml authorization
  off user dba as select from systable
• From a web browser
• Access http//localhost/web/tables

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Thirty Second Web Service
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Thirty Second Web Service

• lt?xml version"1.0" ?gt ltrootgt ltrow
  table_id"1" file_id"0" count"182"
  first_page"1" last_page"620" primary_root"8"
  creator"0" first_ext_page"213"
  last_ext_page"316" table_page_count"19"
  ext_page_count"12" table_name"SYSTABLE"
  table_type"BASE" replicate"N" server_type"SA"
  primary_hash_limit"10" page_map_start"0" /gt
  ltrow table_id"2" file_id"0" count"1325"
  first_page"2" last_page"656" primary_root"9"
  creator"0" first_ext_page"0" last_ext_page"0"
  table_page_count"35" ext_page_count"0"
  table_name"SYSCOLUMN" table_type"BASE"
  replicate"N" server_type"SA" primary_hash_limit
  "10" page_map_start"0" /gt
• ...
• lt/rootgt

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Thirty Second Web Service
C Example static void Main(string args)
XmlTextReader reader new XmlTextReader(
"http//localhost/tables" ) while(
reader.Read() ) switch( reader.NodeType )
case XmlNodeType.Element if( reader.Name
"row" ) Console.WriteLine(
reader.GetAttribute( "table_id" )
) Console.WriteLine( reader.GetAttribute(
"table_name" ) ) break
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Thirty Second Web Service
Python Example import xml.sax class DocHandler(
xml.sax.ContentHandler ) def startElement(
self, name, attrs ) if name
'row' table_id attrs.getValue( 'table_id'
) table_name attrs.getValue( 'table_name'
) print 's s' ( table_id, table_name
) parser xml.sax.make_parser() parser.setCon
tentHandler( DocHandler() ) parser.parse(
'http//localhost/tables' )
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WeatherData

• create table weatherData( year int, day int,
  clock int, humidity float(1), temperature
  float(2), pressure float(1), direction float(1),
  speed float(3) )
• create procedure getWeatherData( in y int, in d
  int )begin select clock, temperature,
  humidity, pressure, direction, speed from
  weatherData where year y and day d order by
  clockend
• create service techwave type 'dish' authorization
  off user dba using "techwave"create service
  "techwave/getWeatherDataXml" type 'xml'
  authorization off user dba as call
  getWeatherData( year, day )create service
  "techwave/getWeatherDataSoap" type 'soap'
  authorization off user dba as call
  getWeatherData( year, day )

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WeatherData
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WeatherData
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WeatherData

• private void button1_Click(object sender,
  System.EventArgs e)
• localhost.techwave service new
  localhost.techwave() DataSet ds null int
  sqlcode
• try ds service.getWeatherDataSoap(
  textBox1.Text, textBox2.Text,
• out sqlcode
  )
• if( sqlcode ! 0 ) MessageBox.Show(
  "Database error, SQLCODE " sqlcode )
  else dataGrid1.DataSource ds
  dataGrid1.DataMember ds.Tables0.TableName
  catch( Exception ex )
  MessageBox.Show( ex.Message )

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WeatherData
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Server Switch

• New server switch -xs
• Controls how the server handles web services
• Valid options
• http listen for http connections
• https listen for https connections
• all listen for both http and https connections
• none don't listen for any connections (default)
• Options
• http and https can take options enclosed in () or
  
• ServerPort
• MyIP
• DatabaseName
• Timeout

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Web Service Statements

• Four new statements
• CREATE SERVICE identifier attributes AS
  statement
• ALTER SERVICE identifier attributes AS
  statement NULL
• DROP SERVICE identifier
• COMMENT ON SERVICE identifier IS comment
• Attributes
• TYPE string
• AUTHORIZATION ON OFF
• SECURE ON OFF
• USER user NULL
• URL PATH ON OFF ELEMENTS
• USING identifier

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Web Service Types

• XML
• query service the result set is returned as XML
• HTML
• query service the result set is returned as HTML
• RAW
• query service the result set is returned as-is
• SOAP
• query service the request is sent as a SOAP
  request and the result set is returned as a SOAP
  response
• DISH
• proxy service DISH services act as a proxies for
  SOAP services
• DISH services also generate WSDL for SOAP services

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Server Addressing

• ltschemegt//lthostgtltportgt/ltdbngt/ltservicegt?ltpar
  amsgt
• scheme http or https
• host hostname or ip address of the server
• port port number the server is listening on
• dbn database that contains the service
• service name of the service
• params list of service parameters
• http//localhost80/web/tables
• http//localhost/tables
• both URLs point to the same service

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Service Determination

• Determine which database will handle the request
• DatabaseName influences this decision
• AUTO
• first element of the path is tried as the
  database name
• if that database doesn't exist, connect to the
  default database
• REQUIRED
• first element of the path is the database name
• dbname
• first element of the path is part of the service
  name
• connect to the database dbname
• Determine which service will handle the request
• URL PATH influences this decision
• check if a service with a name equal to the path
  exists
• if not, remove elements from the path until
• a match is found where URL PATH is ON or ELEMENTS
• the path is empty

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Service Determination Example

• CREATE SERVICE "a" ... URL ELEMENTS
• CREATE SERVICE "a/b" ... URL ON
• CREATE SERVICE "a/c" ... URL OFF
• http//localhost/a/d/e
• handled by "a"
• url1 "d", url2 "e"
• http//localhost/a/b/c/d
• handled by "a/b"
• url "c/d"
• http//localhost/a/c/c
• handled by "a" (not "a/c" since URL is OFF)
• url1 "c", url2 "c"

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Parameter Handling

• Parameters are supplied as
• part of the URL (URL ON ELEMENTS )
• part of the explicit parameter list (e.g,
  http//localhost/service?xy)
• part of the POST data
• part of the SOAP request
• Parameters are declared by specifying host
  variables
• CREATE SERVICE ... AS CALL foo( bar )
• The value of the parameter bar is passed as the
  first parameter to the procedure foo

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Functions and System Procedures

• http_header( name )
• gets the value of an http request header
• next_http_header( name )
• gets the next http request header name
• useful for iterating over request headers
• dbo.sa_set_http_header( name, value )
• sets the value of an http response header
• dbo.sa_set_http_option( name, value )
• sets the value of an http option
• http_variable( name , i )
• gets the ith value of the named host variable
• next_http_variable( name )
• gets the next http host variable name
• useful for iterating over host variables

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Functions and System Procedures

• Example Iterate over all variables
• declare var_name varchar(250)declare var_value
  long varchardeclare i intset var_name
  next_http_variable( NULL )WHILE var_name is not
  NULL LOOP set i 1 set var_value
  http_variable( var_name, i ) WHILE var_value
  is not NULL LOOP // var_value is i'th input
  variable named var_name set i i 1
  set var_value http_variable( var_name, i )
  END LOOP var_name next_http_variable(
  var_name )END LOOP

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