I am working on a n integration project that required me to call a webservice through a stored procedure in the SQL database. After proving my concept using the CLR integration features in Sql Server, I learned that the production database was actually running on Sql Server 2000 compatibility level. There went my proof of concept.
So now I have to resort to doing web service calls the old way, making post requests using MSXML. This is what my stored procedure looks like.
CREATE proc [dbo].[spHTTPRequest]
@URI varchar(2000) = '',
@methodName varchar(50) = '',
@requestBody varchar(8000) = '',
@SoapAction varchar(255),
@UserName nvarchar(100), -- Domain\UserName or UserName
@Password nvarchar(100),
@responseText varchar(8000) output
as
SET NOCOUNT ON
IF @methodName = ''
BEGIN
select FailPoint = 'Method Name must be set'
return
END
set @responseText = 'FAILED'
DECLARE @objectID int
DECLARE @hResult int
DECLARE @source varchar(255), @desc varchar(255)
EXEC @hResult = sp_OACreate 'MSXML2.ServerXMLHTTP', @objectID OUT
IF @hResult <> 0
BEGIN
EXEC sp_OAGetErrorInfo @objectID, @source OUT, @desc OUT
SELECT hResult = convert(varbinary(4), @hResult),
source = @source,
description = @desc,
FailPoint = 'Create failed',
MedthodName = @methodName
goto destroy
return
END
-- open the destination URI with Specified method
EXEC @hResult = sp_OAMethod @objectID, 'open', null, @methodName, @URI, 'false', @UserName, @Password
IF @hResult <> 0
BEGIN
EXEC sp_OAGetErrorInfo @objectID, @source OUT, @desc OUT
SELECT hResult = convert(varbinary(4), @hResult),
source = @source,
description = @desc,
FailPoint = 'Open failed',
MedthodName = @methodName
goto destroy
return
END
-- set request headers
EXEC @hResult = sp_OAMethod @objectID, 'setRequestHeader', null, 'Content-Type', 'text/xml;charset=UTF-8'
IF @hResult <> 0
BEGIN
EXEC sp_OAGetErrorInfo @objectID, @source OUT, @desc OUT
SELECT hResult = convert(varbinary(4), @hResult),
source = @source,
description = @desc,
FailPoint = 'SetRequestHeader failed',
MedthodName = @methodName
goto destroy
return
END
-- set soap action
EXEC @hResult = sp_OAMethod @objectID, 'setRequestHeader', null, 'SOAPAction', @SoapAction
IF @hResult <> 0
BEGIN
EXEC sp_OAGetErrorInfo @objectID, @source OUT, @desc OUT
SELECT hResult = convert(varbinary(4), @hResult),
source = @source,
description = @desc,
FailPoint = 'SetRequestHeader failed',
MedthodName = @methodName
goto destroy
return
END
declare @len int
set @len = len(@requestBody)
EXEC @hResult = sp_OAMethod @objectID, 'setRequestHeader', null, 'Content-Length', @len
IF @hResult <> 0
BEGIN
EXEC sp_OAGetErrorInfo @objectID, @source OUT, @desc OUT
SELECT hResult = convert(varbinary(4), @hResult),
source = @source,
description = @desc,
FailPoint = 'SetRequestHeader failed',
MedthodName = @methodName
goto destroy
return
END
/*
-- if you have headers in a table called RequestHeader you can go through them with this
DECLARE @HeaderKey varchar(500), @HeaderValue varchar(500)
DECLARE RequestHeader CURSOR
LOCAL FAST_FORWARD
FOR
SELECT HeaderKey, HeaderValue
FROM RequestHeaders
WHERE Method = @methodName
OPEN RequestHeader
FETCH NEXT FROM RequestHeader
INTO @HeaderKey, @HeaderValue
WHILE @@FETCH_STATUS = 0
BEGIN
--select @HeaderKey, @HeaderValue, @methodName
EXEC @hResult = sp_OAMethod @objectID, 'setRequestHeader', null, @HeaderKey, @HeaderValue
IF @hResult <> 0
BEGIN
EXEC sp_OAGetErrorInfo @objectID, @source OUT, @desc OUT
SELECT hResult = convert(varbinary(4), @hResult),
source = @source,
description = @desc,
FailPoint = 'SetRequestHeader failed',
MedthodName = @methodName
goto destroy
return
END
FETCH NEXT FROM RequestHeader
INTO @HeaderKey, @HeaderValue
END
CLOSE RequestHeader
DEALLOCATE RequestHeader
*/
-- send the request
EXEC @hResult = sp_OAMethod @objectID, 'send', null, @requestBody
IF @hResult <> 0
BEGIN
EXEC sp_OAGetErrorInfo @objectID, @source OUT, @desc OUT
SELECT hResult = convert(varbinary(4), @hResult),
source = @source,
description = @desc,
FailPoint = 'Send failed',
MedthodName = @methodName
goto destroy
return
END
declare @statusText varchar(1000), @status varchar(1000)
-- Get status text
exec sp_OAGetProperty @objectID, 'StatusText', @statusText out
exec sp_OAGetProperty @objectID, 'Status', @status out
select @status, @statusText, @methodName
-- Get response text
exec sp_OAGetProperty @objectID, 'responseText', @responseText out
IF @hResult <> 0
BEGIN
EXEC sp_OAGetErrorInfo @objectID, @source OUT, @desc OUT
SELECT hResult = convert(varbinary(4), @hResult),
source = @source,
description = @desc,
FailPoint = 'ResponseText failed',
MedthodName = @methodName
goto destroy
return
END
destroy:
exec sp_OADestroy @objectID
SET NOCOUNT OFF
GO
The stored procedure takes the following parameters:
-
@URI: the URI of the web service
-
@MethodName: this would be ‘GET’ or ‘POST’
-
@RequestBody: this is your SOAP xml that you want to send
-
@SoapAction: this the operation that you want to call on your service
-
@UserName: NT UserName if your web service requires authentication
-
@Password: the password if using NT Authentication on the web service
-
@ResponseText: this is an out parameter that contains the response from the web service
Here is a sample call to my service
declare @xmlOut varchar(8000)
Declare @RequestText as varchar(8000);
set @RequestText=
'<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:tem="http://tempuri.org/">
<soapenv:Header/>
<soapenv:Body>
<tem:CreateOrder>
<!--Optional:-->
<tem:OrderRequest>
<tem:OrderId>200</tem:OrderId>
<!--Optional:-->
<tem:OrderName>something</tem:OrderName>
</tem:OrderRequest>
</tem:CreateOrder>
</soapenv:Body>
</soapenv:Envelope>'
exec spHTTPRequest
'http://localhost/testwebservices/helloworldservice.asmx',
'POST',
@RequestText,
'http://tempuri.org/CreateOrderForMe',
'', '', @xmlOut out
select @xmlOut
The stored procedure runs and selects the response from my service call which in my case is:
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
<CreateOrderForMeResponse xmlns="http://tempuri.org/">
<CreateOrderForMeResult>
<Message>Order Created for me</Message>
</CreateOrderForMeResult>
</CreateOrderForMeResponse>
</soap:Body>
</soap:Envelope>
Note that the stored procedure automatically adds the appropriate http headers for Content-Type, SoapAction and Content-Length. If you need to pass additional http headers with your request, refer the section in the center of the stored procedure which is commented out. Basically you need a table in your database called RequestHeaders with 3 columns; HeaderKey, HeaderValue, Method. Populate this table with the keys and values for the additional headers. The Method column will contain GET or POST depending on what method you are using.
Another thing to note here is that I tried the above calls with MSXML2.XMLHTTP and Microsoft.XMLHTTP but did not succeed with either. I kept getting an error from msxml3.dll or msxml6.dll with message "The parameter is incorrect". I believe this to be a bug with msxml that requires the request body text to be in a specific format that is not available through a sql data type and hence cannot be used via TSQL. THese will hoever work fine when performing a simple http request (non- SOAP) or a SOAP request that does not need a request body. for performing SOAP requests from within TSQL the only component that worked for me was MSXML2.ServerXMLHTTP. There are some third-party components that I came across, some paid, but MSXML2.ServerXMLHTTP worked just fine for me.
The next step is to actually take the SOAP response that I recieved and extract the appropriate data from it - that will be another post.
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