Ignoring validation errors during HTTP parsing

It is possible to configure the thumbnail web.config file to ignore any validation errors that occur during HTTP parsing.

Caution

Ignoring validation errors has security implications, so this should only be done as a last resort to gain backward compatibility with a server. However, we recommend that in such a case the software on the server is updated instead, so that it does send valid HTTP messages.

To do so:

1. Open the file C:\Skyline DataMiner\Webpages\VideoThumbnails\Web.config.

2. Add the following option:

   <add key="UseUnsafeHeaderParsing" value="true" />
   

   Note

   When this property is set to false (the default setting), the following validation is performed during HTTP parsing:

   • In end-of-line code, only CRLF is allowed, not CR or LF alone.
   • Headers names may not have spaces in them.
   • If multiple status lines exist, all additional status lines are treated as malformed header name/value pairs.
   • The status line must have a status description, in addition to a status code.

   Regardless of whether the property is set to true or false, header names may not contain non-ASCII characters.

Tip

See also: https://msdn.microsoft.com/en-us/library/system.net.configuration.httpwebrequestelement.useunsafeheaderparsing.aspx