Заказы обработка импортированного файла ошибка разбора content is not allowed in prolog

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<?xml version="1.0" encoding="utf-8"?> 
<ListDomainsResponse xmlns="http://sdb.amazonaws.com/doc/2009-04-15/">
    <ListDomainsResult>
        <DomainName>Audio</DomainName>
        <DomainName>Course</DomainName>
        <DomainName>DocumentContents</DomainName>
        <DomainName>LectureSet</DomainName>
        <DomainName>MetaData</DomainName>
        <DomainName>Professors</DomainName>
        <DomainName>Tag</DomainName>
    </ListDomainsResult>
    <ResponseMetadata>
        <RequestId>42330b4a-e134-6aec-e62a-5869ac2b4575</RequestId>
        <BoxUsage>0.0000071759</BoxUsage>
    </ResponseMetadata>
</ListDomainsResponse>

XMLEventReader eventReader = xmlInputFactory.createXMLEventReader(response.getContent());

com.amazonaws.http.HttpClient handleResponse: Unable to unmarshall response (ParseError at [row,col]:[1,1]
Message: Content is not allowed in prolog.): <?xml version="1.0" encoding="utf-8"?> 
<ListDomainsResponse xmlns="http://sdb.amazonaws.com/doc/2009-04-15/"><ListDomainsResult><DomainName>Audio</DomainName><DomainName>Course</DomainName><DomainName>DocumentContents</DomainName><DomainName>LectureSet</DomainName><DomainName>MetaData</DomainName><DomainName>Professors</DomainName><DomainName>Tag</DomainName></ListDomainsResult><ResponseMetadata><RequestId>42330b4a-e134-6aec-e62a-5869ac2b4575</RequestId><BoxUsage>0.0000071759</BoxUsage></ResponseMetadata></ListDomainsResponse>
javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1]
Message: Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(Unknown Source)
    at com.sun.xml.internal.stream.XMLEventReaderImpl.nextEvent(Unknown Source)
    at com.amazonaws.transform.StaxUnmarshallerContext.nextEvent(StaxUnmarshallerContext.java:153)
    ... (rest of lines omitted)

I’ve been beating my head against this absolutely infuriating bug for the last 48 hours, so I thought I’d finally throw in the towel and try asking here before I throw my laptop out the window.

I’m trying to parse the response XML from a call I made to AWS SimpleDB. The response is coming back on the wire just fine; for example, it may look like:

<?xml version="1.0" encoding="utf-8"?> 
<ListDomainsResponse xmlns="http://sdb.amazonaws.com/doc/2009-04-15/">
    <ListDomainsResult>
        <DomainName>Audio</DomainName>
        <DomainName>Course</DomainName>
        <DomainName>DocumentContents</DomainName>
        <DomainName>LectureSet</DomainName>
        <DomainName>MetaData</DomainName>
        <DomainName>Professors</DomainName>
        <DomainName>Tag</DomainName>
    </ListDomainsResult>
    <ResponseMetadata>
        <RequestId>42330b4a-e134-6aec-e62a-5869ac2b4575</RequestId>
        <BoxUsage>0.0000071759</BoxUsage>
    </ResponseMetadata>
</ListDomainsResponse>

I pass in this XML to a parser with

XMLEventReader eventReader = xmlInputFactory.createXMLEventReader(response.getContent());

and call eventReader.nextEvent(); a bunch of times to get the data I want.

Here’s the bizarre part — it works great inside the local server. The response comes in, I parse it, everyone’s happy. The problem is that when I deploy the code to Google App Engine, the outgoing request still works, and the response XML seems 100% identical and correct to me, but the response fails to parse with the following exception:

com.amazonaws.http.HttpClient handleResponse: Unable to unmarshall response (ParseError at [row,col]:[1,1]
Message: Content is not allowed in prolog.): <?xml version="1.0" encoding="utf-8"?> 
<ListDomainsResponse xmlns="http://sdb.amazonaws.com/doc/2009-04-15/"><ListDomainsResult><DomainName>Audio</DomainName><DomainName>Course</DomainName><DomainName>DocumentContents</DomainName><DomainName>LectureSet</DomainName><DomainName>MetaData</DomainName><DomainName>Professors</DomainName><DomainName>Tag</DomainName></ListDomainsResult><ResponseMetadata><RequestId>42330b4a-e134-6aec-e62a-5869ac2b4575</RequestId><BoxUsage>0.0000071759</BoxUsage></ResponseMetadata></ListDomainsResponse>
javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1]
Message: Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(Unknown Source)
    at com.sun.xml.internal.stream.XMLEventReaderImpl.nextEvent(Unknown Source)
    at com.amazonaws.transform.StaxUnmarshallerContext.nextEvent(StaxUnmarshallerContext.java:153)
    ... (rest of lines omitted)

I have double, triple, quadruple checked this XML for ‘invisible characters’ or non-UTF8 encoded characters, etc. I looked at it byte-by-byte in an array for byte-order-marks or something of that nature. Nothing; it passes every validation test I could throw at it. Even stranger, it happens if I use a Saxon-based parser as well — but ONLY on GAE, it always works fine in my local environment.

It makes it very hard to trace the code for problems when I can only run the debugger on an environment that works perfectly (I haven’t found any good way to remotely debug on GAE). Nevertheless, using the primitive means I have, I’ve tried a million approaches including:

• XML with and without the prolog
• With and without newlines
• With and without the «encoding=» attribute in the prolog
• Both newline styles
• With and without the chunking information present in the HTTP stream

And I’ve tried most of these in multiple combinations where it made sense they would interact — nothing! I’m at my wit’s end. Has anyone seen an issue like this before that can hopefully shed some light on it?

Thanks!

Content is not allowed in prolog error might occur due to unnecessary or invisible characters or JSON code in your XML file or usage of a different encoding format. But you don’t need to worry even if you aren’t sure about the root cause in your case.

This post deals with the causes and solutions for eliminating the same error. Read ahead to see how you can wave goodbye to the error to breathe a sigh of relief.

The sxxp0003: error reported by XML parser: content is not allowed in prolog. is occurring because you have characters at the beginning of your file. There could also be other reasons, like using a different encoding format for parsing, etc.

All possible reasons have been explained below to help you quickly identify the root cause.

– Characters Before the XML Tag

If your file has any characters, such as numbers, symbols, or alphabets, before the XML tag, then you’ll see the given error. The section containing the given tag is called prolog, and it doesn’t allow any characters except for the XML tag inside it.

Here is an example of the problematic beginning of a file:

#<?xml version=”1.0″ encoding=”utf-8″?>

– Incorrectly Typed XML Tag

Adding extra spaces or incorrectly declaring the XML tag can lead to the “parseerror at row col 1 1 message content is not allowed in prolog. Android Studio.” Here is what an incorrectly typed XML tag looks like:

– Using a Different Encoding Format for Parsing

If you create a file with a particular encoding format and then try to parse it with another encoding format, then you’ll get the said error. For example, your XML code has its encoding set to UTF-8. Now, you have created a Java file and set the encoding type for your source file to UTF-16 before parsing the same. Once you run your code to parse XML, the said error will pop up.

The XML and Java code targeting two different encoding formats for creating and parsing the XML code has been attached below.

The XML code created in UTF-8 encoding:

<?xml version=”1.0″ encoding=”utf-8″?>
<week>
<day id=”01″>
<name>Monday</name>
<task>Create five web pages.</task>
<taskDetails><![CDATA[c & d]]></taskDetails>
</day>
<day id=”02″>
<name>Tuesday</name>
<task>Design the pictures.</task>
<taskDetails><![CDATA[x & y]]></taskDetails>
</day>
<day id=”03″>
<name>Wednesday</name>
<task>Write the content.</task>
<taskDetails><![CDATA[a & b]]></taskDetails>
</day>
</week>

The erroneous line in the Java code before parsing the above XML code:

– Your File Begins With Byte Order Mark (BOM)

If your file has BOM at its beginning, you’ll face the same error. In case you don’t know, BOM stands for byte order mark. It points toward using the special Unicode character, such as U+FEFF, before the XML tag.

Even if you can’t see any such characters in your file and can’t recall adding them, they might be there. It is because many text editors automatically add BOM to the UTF-8 files.

– Your File Contains a Combination of XML and JSON

Does your file contain a mixture of XML and JSON content? If yes, it might be the error’s root cause. Note that an XML parser can parse only XML code.

Here is a well-blended file containing both XML and JSON:

{“body”: <<xml version=”1.0″ encoding=”utf-8″?>
<brand>
<writer>John</writer>
<designer>James</designer>
</brand>
, “metadata”: {“one”: “red”, “two”: “blue”, “three”: “green”, “four”: “red”, “five”: “pink”: {“a”:”light pink”,”b”:”tea pink”}}}

Once you try to parse the above code, here is what you’ll see:

org.xml.sax.saxparseexception content is not allowed in prolog

How Do I Fix Content Is Not Allowed in Prolog?

You can fix the stated error by ensuring the accuracy of the XML tag’s syntax and removing the extra characters before it. Also, maintaining consistency between the encoding formats and deleting BOM and non-XML code can help you resolve the error.

Please read on to grasp the solutions’ details.

– Cut Out the Extra Characters and Spaces

You should remove any extra spaces or characters before the XML tag to kill the error. As a single space often goes unnoticed, you can take your cursor at the beginning of the XML tag and click the backspace key. Now, save the changes and try to run your program again to see if it works fine.

– Ensure the Accuracy of the XML Tag

No matter how correct the tag’s syntax looks, you should always ensure that you have written it correctly. It will help you eliminate the error. Here is the valid XML tag for your reference:

<?xml version=”1.0″ encoding=”utf-8″?>

Note that there isn’t any space between “<?” and “xml.” Also, you don’t have to enter a space between “uft-8” and “?>.” Please feel free to copy and paste the given tag into your file to remove the given error.

– Maintain Consistency Between Encoding Formats

To fix an error occurred while parsing content, you must parse your file using the same encoding format you used to create the file. Maintaining consistency between the encoding formats while file creation and parsing can help eliminate the error. If you can’t make changes to the XML parsing code, you should edit the XML tag in your file to match the format used while parsing the same.

Another way to change the encoding format of your file is to save it with your preferred encoding type. For example, you are using Visual Studio to create and edit your files. Now, you want to parse your UTF-8 encoded file using UTF-16 format, but you cannot do it because of the error. Here, you’ll need to follow the below steps to convert your file from UTF-8 to UTF-16 to reach your desired results.

1. Open the File menu.
2. Opt for the option that says Save File As.
3. Look beside the Save button to find the drop-down button.
4. Click the drop-down button to view the Advanced Save Options dialog box.
5. Go to the Encoding section.
6. Choose the encoding format as per your preference.
7. Save the changes.

Remember that the Save File As option isn’t available for the project files. If you wish to convert your project files, then you’ll need to unload the project before converting them.

– Say No To BOM

Saying no to BOM can help your XML code run properly. As stated above, BOM may or may not be visible in your file. Plus, it’s always better to check for the existence of something before attempting to remove it.

So, here is a Java file that’ll check if your file contains BOM and remove it accordingly. Please feel free to use it to remove BOM and, eventually, the error.

import org.apache.commons.codec.binary.Hex;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
public class CutBOM { public static void main(String[] args) throws IOException {
Path filePath = Paths.get(“enter your file’s path here”);
removeBom(filePath);
}
private static boolean isBOMPresent(Path filePath) throws IOException {
if (Files.notExists(filePath)) {
throw new IllegalArgumentException(“The file path: ” + filePath + ” is invalid.”);
}
boolean res = false;
byte[] bomInFile = new byte[3];
try (InputStream myFile = new FileInputStream(filePath.toFile())) {
is.read(bomInFile);
String fileContent = new String(Hex.encodeHex(bomInFile));
if (“efbbbf”.equalsIgnoreCase(fileContent)) {
res = true;
}
}
return res;
}
private static void removeBom(Path filePath) throws IOException {
if (isBOMPresent(filePath)) {
byte[] receivedBytes = Files.readAllBytes(filePath);
ByteBuffer myByteBuffer = ByteBuffer.wrap(receivedBytes);
System.out.println(“BOM exists in your file.”);
byte[] fileBOM = new byte[3];
myByteBuffer.get(fileBOM, 0, fileBOM.length);
byte[] otherContent = new byte[receivedBytes.length – 3];
myByteBuffer.get(otherContent, 0, otherContent.length);
Files.write(filePath, otherContent);
System.out.println(“BOM Removed Successfully!”);
}
else {
System.out.println(“BOM doesn’t exist in your file.”);
}
}
}

– Keep the XML Code Only

If the above solutions don’t work for you, you should check if your file contains JSON or some other code. If you can see it, removing it will make the error disappear.

Conclusion

Now, the error: content is not allowed in prolog won’t confuse you. If it does, you know the path to this article. Read these points to wrap up the post:

• Ensure that your file starts with nothing but a valid XML tag.
• Use the same encoding format for creating and parsing files.
• Get rid of BOM in your file.
• Your file must contain XML code only.

You are ready to resume your work and get things right instantly.