I am Unable to Post Xml to Linkedin Share API - delphi

Question

I am using Delphi 2010, with Indy 10.5.8(svn version) and oAuth.pas from chuckbeasley. I am able to collect token with app key and App secret, authorize token with a web page and Access the final token. Now I have to post a status with Linkedin’s Share API. I am getting a unauthorized response.
My request and responses are giving bellow.
Request,
POST /v1/people/~/shares HTTP/1.0
Content-Encoding: utf-8
Content-Type: text/xml; charset=us-ascii
Content-Length: 999
Authorization: OAuth oauth_consumer_key="xxx",oauth_signature_method="HMAC-SHA1",oauth_timestamp="1340438599",oauth_nonce="BB4C78E0A6EB452BEE0FAA2C3F921FC4",oauth_version="1.0",oauth_token="xxx",oauth_signature="Pz8%2FPz8%2FPz9ePzkxPyc%2FDD82Pz8%3D"
Host: api.linkedin.com
Accept: text/html, */*
Accept-Encoding: identity
User-Agent: Mozilla/3.0 (compatible; Indy Library)
%3C%3Fxml+version=%25221.0%2522%2520encoding%253D%2522UTF-8%2522%253F%253E%253Cshare%253E%253Ccomment%253E83%2525%2520of%2520employers%2520will%2520use%2520social%2520media%2520to%2520hire%253A%252078%2525%2520LinkedIn%252C%252055%2525%2520Facebook%252C%252045%2525%2520Twitter%2520%255BSF%2520Biz%2520Times%255D%2520http%253A%252F%252Fbit.ly%252FcCpeOD%253C%252Fcomment%253E%253Ccontent%253E%253Ctitle%253ESurvey%253A%2520Social%2520networks%2520top%2520hiring%2520tool%2520-%2520San%2520Francisco%2520Business%2520Times%253C%252Ftitle%253E%253Csubmitted-url%253Ehttp%253A%252F%252Fsanfrancisco.bizjournals.com%252Fsanfrancisco%252Fstories%252F2010%252F06%252F28%252Fdaily34.html%253C%252Fsubmitted-url%253E%253Csubmitted-image-url%253Ehttp%253A%252F%252Fimages.bizjournals.com%252Ftravel%252Fcityscapes%252Fthumbs%252Fsm_sanfrancisco.jpg%253C%252Fsubmitted-image-url%253E%253C%252Fcontent%253E%253Cvisibility%253E%253Ccode%253Eanyone%253C%252Fcode%253E%253C%252Fvisibility%253E%253C%252Fshare%253E
Response,
HTTP/1.1 401 Unauthorized
Server: Apache-Coyote/1.1
x-li-request-id: K14SWRPEPL
Date: Sat, 23 Jun 2012 08:07:17 GMT
Vary: *
x-li-format: xml
Content-Type: text/xml;charset=UTF-8
Content-Length: 341
Connection: keep-alive
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<error>
<status>401</status>
<timestamp>1340438838344</timestamp>
<request-id>K14SWRPEPL</request-id>
<error-code>0</error-code>
<message>[unauthorized]. OAU:xxx|nnnnn|*01|*01:1340438599:Pz8/Pz8/Pz9ePzkxPyc/DD82Pz8=</message>
</error>
Please help.
Regards,
Vijesh Nair

Answer 1

I cannot comment on the content of your Authentication header, but the rest of your HTTP request is definately not correct, which tells me that you are not using the TIdHTTP.Post() method correctly. In particular, the XML has been url-encoded TWICE (only one of which would have been Indy's doing), and the Content-Encoding header is wrong.
I suspect that you are making the common newbie mistake of posting the XML using the TStrings overloaded version of TIdHTTP.Post(), and also pre-encoding the XML beforehand. Neither of those will work. You must use the TStream overloaded version instead, and do not pre-encode the XML at all.
The correct request should look more like this:
POST /v1/people/~/shares HTTP/1.0
Content-Type: text/xml; charset=utf-8
Content-Length: 571
Authorization: OAuth oauth_consumer_key="xxx",oauth_signature_method="HMAC-SHA1",oauth_timestamp="1340438599",oauth_nonce="BB4C78E0A6EB452BEE0FAA2C3F921FC4",oauth_version="1.0",oauth_token="xxx",oauth_signature="Pz8%2FPz8%2FPz9ePzkxPyc%2FDD82Pz8%3D"
Host: api.linkedin.com
Accept: text/html, */*
Accept-Encoding: identity
User-Agent: Mozilla/3.0 (compatible; Indy Library)
<?xml version="1.0" encoding="UTF-8"?><share><comment>83% of employers will use social media to hire: 78% LinkedIn, 55% Facebook, 45% Twitter [SF Biz Times] http://bit.ly/cCpeOD</comment><content><title>Survey: Social networks top hiring tool - San Francisco Business Times</title><submitted-url>http://sanfrancisco.bizjournals.com/sanfrancisco/stories/2010/06/28/daily34.html</submitted-url><submitted-image-url>http://images.bizjournals.com/travel/cityscapes/thumbs/sm_sanfrancisco.jpg</submitted-image-url></content><visibility><code>anyone</code></visibility></share>
The code to produce that request should look something like this:
var
PostData: TMemoryStream;
begin
PostData := TMemoryStream.Create;
try
WriteStringToStream(PostData, '<?xml version="1.0" encoding="UTF-8"?><share><comment>83% of employers will use social media to hire: 78% LinkedIn, 55% Facebook, 45% Twitter [SF Biz Times] http://bit.ly/cCpeOD</comment><content><title>Survey: Social networks top hiring tool - San Francisco Business Times</title><submitted-url>http://sanfrancisco.bizjournals.com/sanfrancisco/stories/2010/06/28/daily34.html</submitted-url><submitted-image-url>http://images.bizjournals.com/travel/cityscapes/thumbs/sm_sanfrancisco.jpg</submitted-image-url></content><visibility><code>anyone</code></visibility></share>', IndyUTF8Encoding);
PostData.Position := 0;
IdHTTP1.Request.ContentType := 'text/xml';
IdHTTP1.Request.Charset := 'utf-8';
IdHTTP1.Request.CustomHeaders.Values['Authorization'] := 'OAuth oauth_consumer_key="xxx",oauth_signature_method="HMAC-SHA1",oauth_timestamp="1340438599",oauth_nonce="BB4C78E0A6EB452BEE0FAA2C3F921FC4",oauth_version="1.0",oauth_token="xxx",oauth_signature="Pz8%2FPz8%2FPz9ePzkxPyc%2FDD82Pz8%3D"';
IdHTTP1.Post('http://api.linkedin.com/v1/people/~/shares', PostData);
finally
PostData.Free;
end;