Searching for document signatures excluding external components Leave feedback
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GroupDocs.Signature provides boolean property SkipExternal of SearchOptions class to specify if searching process should exclude external signatures (external signatures are the signatures that were added with an 3rd party software and not with GroupDocs.Signature).
Since 19.12 version every time when document is being signed information about document signatures are stored in document’s metadata. Which means that all created signatures by GroupDocs.Signature can be distinguished from an actual document content and IsSignature flag will be set as true. IsSignature property specifies if document component (text/image/barcode/qr-code) is the actual signature or element of document content.
In order to convert signatures added by 3rd party software or by previous version of GroupDocs.Signature, just run Search withSkipExternal property set to false (this is default value) and update IsSignature for each signature returned by the search result.
There are few ways to manipulate with document signature search results:
- If signature is no longer required it can be removed from the document by Delete method;
- Signature could be marked as document native content by setting up IsSignature = false property,in this case SkipExternal field will allow Search method to skip this signature;
- Signatures that were added before 19.12 are treated as non signatures because information about them are not yet stored in the document. Setting SkipExternal flag to true will exclude these signatures from Search result.
Here are the steps to search for signatures and exclude external components of the document with GroupDocs.Signature:
- Create new instance of Signature class and pass source document path as a constructor parameter.
- Instantiate the SearchOptions object according to your requirements and specify SkipExternal to true
- Call Search method of Signature class instance and pass SearchOptions to it.
Following example demonstrates usage of SkipExternal property for excluding non actual signatures from search result
using (Signature signature = new Signature("sample_signed.pdf"))
{
TextSearchOptions options = new TextSearchOptions()
{
// specify SkipExternal value to exclude non signature objects from Search result
SkipExternal = true,
// specify search on all pages
AllPages = false
};
// search for text signatures in document
List<TextSignature> signatures = signature.Search<TextSignature>(options);
Console.WriteLine("\nSource document contains following text signature(s).");
// enumerate all signature for output
foreach (TextSignature textSignature in signatures)
{
if (textSignature != null)
{
Console.WriteLine($"Found Text signature at page {textSignature.PageNumber} with type [{textSignature.SignatureImplementation}] and text '{textSignature.Text}'.");
Console.WriteLine($"Location at {textSignature.Left}-{textSignature.Top}. Size is {textSignature.Width}x{textSignature.Height}.");
}
}
}
Following examples shows the way to mark signatures in document as actual signatures (IsSignature = true)
// initialize Signature instance
using (Signature signature = new Signature("sample_signed.pdf"))
{
// define search options to select required signatures om the document
BarcodeSearchOptions barcodeOptions = new BarcodeSearchOptions();
QrCodeSearchOptions qrCodeOptions = new QrCodeSearchOptions();
TextSearchOptions textOptions = new TextSearchOptions();
// add options to list
List<SearchOptions> listOptions = new List<SearchOptions>();
listOptions.Add(barcodeOptions);
listOptions.Add(qrCodeOptions);
listOptions.Add(textOptions);
// search for signatures in document
SearchResult result = signature.Search(listOptions);
if (result.Signatures.Count > 0)
{
Console.WriteLine("\nTrying to update all signatures...");
// mark all signatures as actual Signatures
foreach(BaseSignature baseSignature in result.Signatures)
{
baseSignature.IsSignature = true;
}
// update all found signatures
UpdateResult updateResult = signature.Update(result.Signatures);
if(updateResult.Succeeded.Count == result.Signatures.Count)
{
Console.WriteLine("\nAll signatures were successfully updated!");
}
else
{
Console.WriteLine($"Successfully updated signatures : {updateResult.Succeeded.Count}");
Console.WriteLine($"Not updated signatures : {updateResult.Failed.Count}");
}
Console.WriteLine("\nList of updated signatures:");
int number = 1;
foreach(BaseSignature temp in updateResult.Succeeded)
{
Console.WriteLine($"Signature #{number++}: Type: {temp.SignatureType} Id:{temp.SignatureId}, Location: {temp.Left}x{temp.Top}. Size: {temp.Width}x{temp.Height}");
}
}
else
{
Console.WriteLine("No one signature was found.");
}
}
You may easily run the code above and see the feature in action in our GitHub examples:
- GroupDocs.Signature for .NET examples, plugins, and showcase
- GroupDocs.Signature for Java examples, plugins, and showcase
- Document Signature for .NET MVC UI Example
- Document Signature for .NET App WebForms UI Example
- Document Signature for Java App Dropwizard UI Example
- Document Signature for Java Spring UI Example
Along with the full-featured .NET library, we provide simple but powerful free online apps.
To sign PDF, Word, Excel, PowerPoint, and other documents you can use the online apps from the GroupDocs.Signature App Product Family.
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