VTD-XML Exception: Name space qualification Exception: prefixed attribute not qualified - vtd-xml

I receive an XML via a web service and I am using legacy code (which uses dom4j) to perform some xml transformation. Loading/parsing the original XML into VTD-XML (VTDGen) works fine, no exceptions thrown. However, after loading the xml into dom4j, I noticed some of the element namespace declarations and attributes are re-arranged. Apparently, this re-arrangement causes VTD-XML to throw the following exception:
Exception:
Name space qualification Exception: prefixed attribute not qualified
Line Number: 101 Offset: 1827
Here is the element at this line number in the original XML:
<RR_PerformanceSite:PerformanceSite_1_4 RR_PerformanceSite:FormVersion="1.4" xmlns:NSF_ApplicationChecklist="http://apply.grants.gov/forms/NSF_ApplicationChecklist-V1.1" xmlns:NSF_CoverPage="http://apply.grants.gov/forms/NSF_CoverPage-V1.1" xmlns:NSF_DeviationAuthorization="http://apply.grants.gov/forms/NSF_DeviationAuthorization-V1.1" xmlns:NSF_Registration="http://apply.grants.gov/forms/NSF_Registration-V1.1" xmlns:NSF_SuggestedReviewers="http://apply.grants.gov/forms/NSF_SuggestedReviewers-V1.1" xmlns:PHS398_CareerDevelopmentAwardSup="http://apply.grants.gov/forms/PHS398_CareerDevelopmentAwardSup_1_1-V1.1" xmlns:PHS398_Checklist="http://apply.grants.gov/forms/PHS398_Checklist_1_3-V1.3" xmlns:PHS398_CoverPageSupplement="http://apply.grants.gov/forms/PHS398_CoverPageSupplement_1_4-V1.4" xmlns:PHS398_ModularBudget="http://apply.grants.gov/forms/PHS398_ModularBudget-V1.1" xmlns:PHS398_ResearchPlan="http://apply.grants.gov/forms/PHS398_ResearchPlan_1_3-V1.3" xmlns:PHS_CoverLetter="http://apply.grants.gov/forms/PHS_CoverLetter_1_2-V1.2" xmlns:RR_Budget="http://apply.grants.gov/forms/RR_Budget-V1.1" xmlns:RR_KeyPersonExpanded="http://apply.grants.gov/forms/RR_KeyPersonExpanded_1_2-V1.2" xmlns:RR_OtherProjectInfo="http://apply.grants.gov/forms/RR_OtherProjectInfo_1_2-V1.2" xmlns:RR_PerformanceSite="http://apply.grants.gov/forms/PerformanceSite_1_4-V1.4" xmlns:RR_PersonalData="http://apply.grants.gov/forms/RR_PersonalData-V1.1" xmlns:RR_SF424="http://apply.grants.gov/forms/RR_SF424_1_2-V1.2" xmlns:RR_SubawardBudget="http://apply.grants.gov/forms/RR_SubawardBudget-V1.2" xmlns:SF424C="http://apply.grants.gov/forms/SF424C-V1.0" xmlns:att="http://apply.grants.gov/system/Attachments-V1.0" xmlns:codes="http://apply.grants.gov/system/UniversalCodes-V2.0" xmlns:globlib="http://apply.grants.gov/system/GlobalLibrary-V2.0">
Here is the same element after loaded into dom4j:
<RR_PerformanceSite:PerformanceSite_1_4 xmlns:RR_PerformanceSite="http://apply.grants.gov/forms/PerformanceSite_1_4-V1.4" xmlns:NSF_ApplicationChecklist="http://apply.grants.gov/forms/NSF_ApplicationChecklist-V1.1" xmlns:NSF_CoverPage="http://apply.grants.gov/forms/NSF_CoverPage-V1.1" xmlns:NSF_DeviationAuthorization="http://apply.grants.gov/forms/NSF_DeviationAuthorization-V1.1" xmlns:NSF_Registration="http://apply.grants.gov/forms/NSF_Registration-V1.1" xmlns:NSF_SuggestedReviewers="http://apply.grants.gov/forms/NSF_SuggestedReviewers-V1.1" xmlns:PHS398_CareerDevelopmentAwardSup="http://apply.grants.gov/forms/PHS398_CareerDevelopmentAwardSup_1_1-V1.1" xmlns:PHS398_Checklist="http://apply.grants.gov/forms/PHS398_Checklist_1_3-V1.3" xmlns:PHS398_CoverPageSupplement="http://apply.grants.gov/forms/PHS398_CoverPageSupplement_1_4-V1.4" xmlns:PHS398_ModularBudget="http://apply.grants.gov/forms/PHS398_ModularBudget-V1.1" xmlns:PHS398_ResearchPlan="http://apply.grants.gov/forms/PHS398_ResearchPlan_1_3-V1.3" xmlns:PHS_CoverLetter="http://apply.grants.gov/forms/PHS_CoverLetter_1_2-V1.2" xmlns:RR_Budget="http://apply.grants.gov/forms/RR_Budget-V1.1" xmlns:RR_KeyPersonExpanded="http://apply.grants.gov/forms/RR_KeyPersonExpanded_1_2-V1.2" xmlns:RR_OtherProjectInfo="http://apply.grants.gov/forms/RR_OtherProjectInfo_1_2-V1.2" xmlns:RR_PersonalData="http://apply.grants.gov/forms/RR_PersonalData-V1.1" xmlns:RR_SF424="http://apply.grants.gov/forms/RR_SF424_1_2-V1.2" xmlns:RR_SubawardBudget="http://apply.grants.gov/forms/RR_SubawardBudget-V1.2" xmlns:SF424C="http://apply.grants.gov/forms/SF424C-V1.0" xmlns:att="http://apply.grants.gov/system/Attachments-V1.0" xmlns:codes="http://apply.grants.gov/system/UniversalCodes-V2.0" xmlns:globlib="http://apply.grants.gov/system/GlobalLibrary-V2.0" RR_PerformanceSite:FormVersion="1.4">
The problem is regarding the attribute (at offset 1827, at the end of the element) in the new XML element: RR_PerformanceSite:FormVersion="1.4"
Here is what removes the exception:
1. Adding the RR_PerformanceSite xmlns declaration for this element to the root element of the XML doc.
2. Replacing new element with original element. This SEEMS to lead me to believe that the order of the attributes/ns declarations affects VTD when parsing.
NOTE: I parse the xml doc setting ns aware to 'true' with both xml docs (original and post-dom4j xml). Also, new VTD objects are created for each xml, original and post-dom4j.
I tried to put 'RR_PerformanceSite:FormVersion="1.4"' at the beginning of the element like the original but that does not remove the exception. The offset in the error message is different due to the change of location of the attribute. Does the order of the xmlns declarations affect VTD?
I have looked at the VTDGen source code and cannot figure out why this exception is being thrown.
Why would dom4j parse the new doc and vtd is unable to? Can anyone can shed some light on this?

It appears to be a bug on VTD-XML, related with namespace declaration order.
Always reproducible using the following Java code
public class SchemaTester {
/**
* #param args
*/
public static void main(String[] args) throws Exception {
String bad = "C:/Temp/VTD_bad.xml"; // XML files to test
String good = "C:/Temp/VTD_good.xml";
StringBuilder sb = new StringBuilder();
char[] buf = new char[4*1024];
FileReader fr = new FileReader(bad);
int readed = 0;
while ((readed = fr.read(buf, 0, buf.length)) != -1) {
sb.append(buf, 0, readed);
}
fr.close();
String x = sb.toString();
//instantiate VTDGen
//and call parse
VTDGen vg = new VTDGen();
vg.setDoc(x.getBytes("UTF-8"));
vg.parse(true); // set namespace awareness to true
VTDNav vn = vg.getNav();
AutoPilot ap = new AutoPilot (vn);
ap.selectXPath("//*/#*");
int i= -1;
while((i=ap.evalXPath()) != -1) {
// i will be attr name, i+1 will be attribute value
System.out.println("\t\tAttribute ==> " + vn.toNormalizedString(i));
System.out.println("\t\tValue ==> " + vn.toNormalizedString(i+1));
}
}
}
The OP has uploaded the XML to https://gist.github.com/2696220

Related

Converting XDP to PDF using Live Cycle replaces question marks(?) with space at multiple places. How can that be fixed?

I have been trying to convert XDP to PDF using Adobe Live Cycle. Most of my forms turn up good. But while converting some of them, I fine ??? replaced in place of blank spaces at certain places. Any suggestions to how can I rectify that?
Below is the code snippet that I am using:
public byte[] generatePDF(TextDocument xdpDocument) {
try {
Assert.notNull(xdpDocument, "XDP Document must be passed.");
Assert.hasLength(xdpDocument.getContent(), "XDPDocument content cannot be null");
// Create a ServiceClientFactory object
ServiceClientFactory myFactory = ServiceClientFactory.createInstance(createConnectionProperties());
// Create an OutputClient object
FormsServiceClient formsClient = new FormsServiceClient(myFactory);
formsClient.resetCache();
String text = xdpDocument.getContent();
String charSet = xdpDocument.getCharsetName();
if (charSet == null || charSet.trim().length() == 0) {
charSet = StandardCharsets.UTF_8.name();
}
byte[] bytes = text.getBytes();
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(bytes);
Document inTemplate = new Document(byteArrayInputStream);
// Set PDF run-time options
// Set rendering run-time options
RenderOptionsSpec renderOptionsSpec = new RenderOptionsSpec();
renderOptionsSpec.setLinearizedPDF(true);
renderOptionsSpec.setAcrobatVersion(AcrobatVersion.Acrobat_9);
PDFFormRenderSpec pdfFormRenderSpec = new PDFFormRenderSpec();
pdfFormRenderSpec.setGenerateServerAppearance(true);
pdfFormRenderSpec.setCharset("UTF8");
FormsResult formOut = formsClient.renderPDFForm2(inTemplate, null, pdfFormRenderSpec, null, null);
Document xfaPdfOutput = formOut.getOutputContent();
//If the input file is already static PDF, then below method will throw an exception - handle it
OutputClient outClient = new OutputClient(myFactory);
outClient.resetCache();
Document staticPdfOutput = outClient.transformPDF(xfaPdfOutput, TransformationFormat.PDF, null, null, null);
byte[] data = StreamIO.toBytes(staticPdfOutput.getInputStream());
return data;
} catch(IllegalArgumentException ex) {
logger.error("Input validation failed for generatePDF request " + ex.getMessage());
throw new EformsException(ErrorExceptionCode.INPUT_REQUIRED + " - " + ex.getMessage(), ErrorExceptionCode.INPUT_REQUIRED);
} catch (Exception e) {
logger.error("Exception occurred in Adobe Services while generating PDF from xdpDocument..", e);
throw new EformsException(ErrorExceptionCode.PDF_XDP_CONVERSION_EXCEPTION, e);
}
}
I suggest trying 2 things:
Check the font. Switch to something very common like Arial / Times New Roman and see if the characters are still lost
Check the character encoding. It might not be a simple question mark character you are using and if so the character encoding will be important. The easiest way is to make sure your question mark is ascii char 63 (decimal).
I hope that helps.

Error occurred creating story: "Cannot parse object reference from", Rally

I am trying to create user stories in rally by java. Am failing to get response and it throwing " Cannot parse object reference from ".
Brief on my rally : Let assume I have Project name "Characters" and its has subs as A, B, C, D. I have to create my user stories in C. Is my following code correct in this prospect? Can anyone please help?
package samplerally;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import com.google.gson.JsonObject;
import com.rallydev.rest.RallyRestApi;
import com.rallydev.rest.request.CreateRequest;
import com.rallydev.rest.request.GetRequest;
import com.rallydev.rest.response.CreateResponse;
import com.rallydev.rest.util.Ref;
public class CreateStory {
public static void main(String[] args) throws URISyntaxException,IOException {
String host = "https://rally1.rallydev.com";
String username = "name#comp.com";
String password = "password";
String wsapiVersion = "v2.0";
String applicationName = "C";
RallyRestApi restApi = new RallyRestApi(new URI(host),username,password);
restApi.setWsapiVersion(wsapiVersion);
restApi.setApplicationName(applicationName);
try {
for (int i = 0; i < 3; i++) {
// Add a story
System.out.println("Creating a story...");
JsonObject newStory = new JsonObject();
newStory.addProperty("Name", "my story");
newStory.addProperty("Project", "Characters");
CreateRequest createRequest = new CreateRequest("hierarchicalrequirement", newStory);
CreateResponse createResponse = restApi.create(createRequest);
System.out.println("Response ::: "+createResponse.wasSuccessful());
if (createResponse.wasSuccessful()) {
System.out.println(String.format("Created %s",createResponse.getObject().get("_ref").getAsString()));
// Read story
String ref = Ref.getRelativeRef(createResponse.getObject().get("_ref").getAsString());
System.out.println(String.format("\nReading Story %s...",ref));
GetRequest getRequest = new GetRequest(ref);
} else {
String[] createErrors;
createErrors = createResponse.getErrors();
System.out.println("Error occurred creating story: ");
for (int j = 0; j < createErrors.length; j++) {
System.out.println(createErrors[j]);
}
}
}
} finally {
// Release all resources
restApi.close();
}
}
}
And I am getting error as :
Creating a story...
Response ::: false
Error occurred creating story:
Could not read: Cannot parse object reference from "BSS HWSE Team Columbia"
Creating a story...
Response ::: false
Error occurred creating story:
Could not read: Cannot parse object reference from "BSS HWSE Team Columbia"
Creating a story...
Response ::: false
Error occurred creating story:
Could not read: Cannot parse object reference from "BSS HWSE Team Columbia"
Picked up JAVA_TOOL_OPTIONS: -agentlib:jvmhook
Picked up _JAVA_OPTIONS: -Xrunjvmhook -Xbootclasspath/a:"C:\Program Files\HP\Unified Functional Testing\bin\java_shared\classes";"C:\Program Files\HP\Unified Functional Testing\bin\java_shared\classes\jasmine.jar"
Please help. New to rally. Thanks in advance
When setting reference fields such as Project, Iteration, Release, WorkProduduct, Parent, etc that point to full objects use the reference,and not the Name.
Find out the unique ObjectID of the Project "C", e.g. 123456.
Replace:
newStory.addProperty("Project", "Characters");
with
newStory.addProperty("Project", "/project/123456");
To find ObjectID of a project you may either query by its name in WS API, or look at the URL of one of Rally pages in the address bar, while in that project, e.g. URL of a Backlog page: https://rally1.rallydev.com/#/123456/backlog
If there is a d or u appended to ObjectID string, e.g. 123456d, do not include it in string. In the URL it indicates if you are currently scoping up or down.

Error creating PDF with Zend (fontWithName)

I'm trying to generate a PDF file using Zend but I keep getting errors when trying to set the font.
Here is my code:
$pdf = new Zend_Pdf();
$page = new Zend_Pdf_Page(Zend_Pdf_Page::SIZE_A4);
$font = new Zend_Pdf_Font::fontWithName(Zend_Pdf_Font::FONT_HELVETICA);
$page->setFont($font,24)
->drawText("Hello world!",72,720);
$pdf->$page;
$pdf->save("example.pdf");
And this is the error:
Parse error: syntax error, unexpected 'fontWithName' (T_STRING), expecting variable (T_VARIABLE) or '$' in /Users/pawel/Sites/Zend/application/modules/default/controllers/IndexController.php on line 83
I think you can just remove new for the font declaration:
$font = Zend_Pdf_Font::fontWithName(Zend_Pdf_Font::FONT_HELVETICA);
$style = new Zend_Pdf_Style();
$style->setFont($font, 24);
$page->setStyle($style);
fontWithName is a static function and Zend_Pdf_Font is an abstract class.
See the documentation for example.
There is another problem:
Replace
$pdf->$page;
by
$pdf->pages[] = $page;

Split a "tagged" PDF document into multiple documents, keeping the tagging

In a project I have to split a PDF document into two documents, one containing all blank pages, and one containing all pages with content.
For this job, I use a PdfReader to read the source file, and two pdfCopy objects (one for the blank pages document, one for the pages with content document) to write the files to.
I use GetImportedPage to read a PdfImportedPage, which is then added to one of the PdfCopy writers.
Now, the problem is the following: the source file is using the "tagged PDF format". To preserve this (which is absolutely required), I use the SetTagged() method on both PdfCopy writers, and use the extra third parameter in GetImportedPage(...) to keep the tagged format. However, when calling the AddPage(...) on the PdfCopy writer, I get an invalid cast exception:
"Unable to cast object of type 'iTextSharp.text.pdf.PdfDictionary' to type 'iTextSharp.text.pdf.PRIndirectReference'."
Anyone has any ideas on how to solve this ? Any hints ?
Also: the project currently refers version 5.1.0.0 of the itext libraries. In 5.4.4.0 the third parameter to GetImportedPage does not seem to be there anymore.
Below, you can find a code extract:
iTextSharp.text.Document targetPdf = new iTextSharp.text.Document();
iTextSharp.text.Document blankPdf = new iTextSharp.text.Document();
iTextSharp.text.pdf.PdfReader sourcePdfReader = new iTextSharp.text.pdf.PdfReader(inputFile);
iTextSharp.text.pdf.PdfCopy targetPdfWriter = new iTextSharp.text.pdf.PdfSmartCopy(targetPdf, new FileStream(outputFile, FileMode.Create));
iTextSharp.text.pdf.PdfCopy blankPdfWriter = new iTextSharp.text.pdf.PdfSmartCopy(blankPdf, new FileStream(blanksFile, FileMode.Append));
targetPdfWriter.SetTagged();
blankPdfWriter.SetTagged();
try
{
iTextSharp.text.pdf.PdfImportedPage page = null;
int n = sourcePdfReader.NumberOfPages;
targetPdf.Open();
blankPdf.Open();
blankPdf.Add(new iTextSharp.text.Phrase("This document contains the blank pages removed from " + inputFile));
blankPdf.NewPage();
for (int i = 1; i <= n; i++)
{
byte[] pageBytes = sourcePdfReader.GetPageContent(i);
string pageText = "";
iTextSharp.text.pdf.PRTokeniser token = new iTextSharp.text.pdf.PRTokeniser(new iTextSharp.text.pdf.RandomAccessFileOrArray(pageBytes));
while (token.NextToken())
{
if (token.TokenType == iTextSharp.text.pdf.PRTokeniser.TokType.STRING)
{
pageText += token.StringValue;
}
}
if (pageText.Length >= 15)
{
page = targetPdfWriter.GetImportedPage(sourcePdfReader, i, true);
targetPdfWriter.AddPage(page);
}
else
{
page = blankPdfWriter.GetImportedPage(sourcePdfReader, i, true);
blankPdfWriter.AddPage(page);
blankPageCount++;
}
}
}
catch (Exception ex)
{
Console.WriteLine("Exception at LOC1: " + ex.Message);
}
The error occurs in the call to targetPdfWriter.AddPage(page); near the end of the code sample.
Thank you very much for your help.
Koen.

The ':' character, hexadecimal value 0x3A, cannot be included in a name

I saw this question already, but I didnt see an answer..
So I get this error:
The ':' character, hexadecimal value 0x3A, cannot be included in a name.
On this code:
XDocument XMLFeed = XDocument.Load("http://feeds.foxnews.com/foxnews/most-popular?format=xml");
XNamespace content = "http://purl.org/rss/1.0/modules/content/";
var feeds = from feed in XMLFeed.Descendants("item")
select new
{
Title = feed.Element("title").Value,
Link = feed.Element("link").Value,
pubDate = feed.Element("pubDate").Value,
Description = feed.Element("description").Value,
MediaContent = feed.Element(content + "encoded")
};
foreach (var f in feeds.Reverse())
{
....
}
An item looks like that:
<rss>
<channel>
....items....
<item>
<title>Pentagon confirms plan to create new spy agency</title>
<link>http://feeds.foxnews.com/~r/foxnews/most-popular/~3/lVUZwCdjVsc/</link>
<category>politics</category>
<dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/" />
<pubDate>Tue, 24 Apr 2012 12:44:51 PDT</pubDate>
<guid isPermaLink="false">http://www.foxnews.com/politics/2012/04/24/pentagon-confirms-plan-to-create-new-spy-agency/</guid>
<content:encoded xmlns:content="http://purl.org/rss/1.0/modules/content/"><![CDATA[|http://global.fncstatic.com/static/managed/img/Politics/panetta_hearing_030712.jpg<img src="http://feeds.feedburner.com/~r/foxnews/most-popular/~4/lVUZwCdjVsc" height="1" width="1"/>]]></content:encoded>
<description>The Pentagon confirmed Tuesday that it is carving out a brand new spy agency expected to include several hundred officers focused on intelligence gathering around the world.&amp;#160;</description>
<dc:date xmlns:dc="http://purl.org/dc/elements/1.1/">2012-04-4T19:44:51Z</dc:date>
<feedburner:origLink>http://www.foxnews.com/politics/2012/04/24/pentagon-confirms-plan-to-create-new-spy-agency/</feedburner:origLink>
</item>
....items....
</channel>
</rss>
All I want is to get the "http://global.fncstatic.com/static/managed/img/Politics/panetta_hearing_030712.jpg", and before that check if content:encoded exists..
Thanks.
EDIT:
I've found a sample that I can show and edit the code that tries to handle it..
EDIT2:
I've done it in the ugly way:
text.Replace("content:encoded", "contentt").Replace("xmlns:content=\"http://purl.org/rss/1.0/modules/content/\"","");
and then get the element in the normal way:
MediaContent = feed.Element("contentt").Value
The following code
static void Main(string[] args)
{
var XMLFeed = XDocument.Parse(
#"<rss>
<channel>
....items....
<item>
<title>Pentagon confirms plan to create new spy agency</title>
<link>http://feeds.foxnews.com/~r/foxnews/most-popular/~3/lVUZwCdjVsc/</link>
<category>politics</category>
<dc:creator xmlns:dc='http://purl.org/dc/elements/1.1/' />
<pubDate>Tue, 24 Apr 2012 12:44:51 PDT</pubDate>
<guid isPermaLink='false'>http://www.foxnews.com/politics/2012/04/24/pentagon-confirms-plan-to-create-new-spy-agency/</guid>
<content:encoded xmlns:content='http://purl.org/rss/1.0/modules/content/'><![CDATA[|http://global.fncstatic.com/static/managed/img/Politics/panetta_hearing_030712.jpg<img src='http://feeds.feedburner.com/~r/foxnews/most-popular/~4/lVUZwCdjVsc' height='1' width='1'/>]]></content:encoded>
<description>The Pentagon confirmed Tuesday that it is carving out a brand new spy agency expected to include several hundred officers focused on intelligence gathering around the world.&amp;#160;</description>
<dc:date xmlns:dc='http://purl.org/dc/elements/1.1/'>2012-04-4T19:44:51Z</dc:date>
<!-- <feedburner:origLink>http://www.foxnews.com/politics/2012/04/24/pentagon-confirms-plan-to-create-new-spy-agency/</feedburner:origLink> -->
</item>
....items....
</channel>
</rss>");
XNamespace contentNs = "http://purl.org/rss/1.0/modules/content/";
var feeds = from feed in XMLFeed.Descendants("item")
select new
{
Title = (string)feed.Element("title"),
Link = (string)feed.Element("link"),
pubDate = (string)feed.Element("pubDate"),
Description = (string)feed.Element("description"),
MediaContent = GetMediaContent((string)feed.Element(contentNs + "encoded"))
};
foreach(var item in feeds)
{
Console.WriteLine(item);
}
}
private static string GetMediaContent(string content)
{
int imgStartPos = content.IndexOf("<img");
if(imgStartPos > 0)
{
int startPos = content[0] == '|' ? 1 : 0;
return content.Substring(startPos, imgStartPos - startPos);
}
return string.Empty;
}
results in:
{ Title = Pentagon confirms plan to create new spy agency, Link = http://feeds.f
oxnews.com/~r/foxnews/most-popular/~3/lVUZwCdjVsc/, pubDate = Tue, 24 Apr 2012 1
2:44:51 PDT, Description = The Pentagon confirmed Tuesday that it is carving out
a brand new spy agency expected to include several hundred officers focused on
intelligence gathering around the world. , MediaContent = http://global
.fncstatic.com/static/managed/img/Politics/panetta_hearing_030712.jpg }
Press any key to continue . . .
A few points:
You never want to treat Xml as text - in your case you removed the namespace declaration but actually if the namespace was declared inline (i.e. without binding to the prefix) or a different prefix would be defined your code would not work even though semantically both documents would be equivalent
Unless you know what's inside CDATA and how to treat it you always want to treat is as text. If you know it's something else you can treat it differently after parsing - see my elaborate on CDATA below for more details
To avoid NullReferenceExceptions if the element is missing I used explicit conversion operator (string) instead of invoking .Value
the Xml you posted was not a valid xml - there was missing namespace Uri for feedburner prefix
This is no longer related to the problem but may be helpful for some folks so I am leaving it
As far as the contents of the encode element is considered it is inside CDATA section. What's inside CDATA section is not an Xml but plain text. CDATA is usually used to not have to encode '<', '>', '&' characters (without CDATA they would have to be encoded as < > and & to not break the Xml document itself) but the Xml processor treat characters in the CDATA as if they were encoded (or to be more correct in encodes them). The CDATA is convenient if you want to embed html because textually the embedded content looks like the original yet it won't break your xml if the html is not a well-formed Xml. Since the CDATA content is not an Xml but text it is not possible to treat it as Xml. You will probably need to treat is as text and use for instance regular expressions. If you know it is a valid Xml you can load the contents to an XElement again and process it. In your case you have got mixed content so it is not easy to do unless you use a little dirty hack. Everything would be easy if you have just one top level element instead of mixed content. The hack is to add the element to avoid all the hassle. Inside the foreach look you can do something like this:
var mediaContentXml = XElement.Parse("<content>" + (string)item.MediaContent + "</content>");
Console.WriteLine((string)mediaContentXml.Element("img").Attribute("src"));
Again it's not pretty and it is a hack but it will work if the content of the encoded element is valid Xml. The more correct way of doing this is to us XmlReader with ConformanceLevel set to Fragment and recognize all kinds of nodes appropriately to create a corresponding Linq to Xml node.
You should use XNamespace:
XNamespace content = "...";
// later in your code ...
MediaContent = feed.Element(content + "encoded")
See more details here.
(Of course, you the string to be assigned to content is the same as in xmlns:content="...").