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We're having trouble setting a BaseUrl using iTextSharp. We have used Adobes Implementation for this in the past, but we got some severe performance issues. So we switched to iTextSharp, which is aprox 10 times faster. Adobe enabled us to set a base url for each document. We really need this in order to deploy our documents on different servers. But we cant seem to find the right code to do this.

This code is what we used with Adobe:

public bool SetBaseUrl(object jso, string baseUrl)
{
    try
    {
        object result = jso.GetType().InvokeMember("baseURL", BindingFlags.SetProperty, null, jso, new Object[] {baseUrl });
        return result != null;
    }
    catch
    {
        return false;
    }
}

A lot of solutions describe how you can insert links in new or empty documents. But our documents already exist and do contain more than just text. We want to overlay specific words with a link that leads to one or more other documents. Therefore, its really important to us that we can insert a link without accessing the text itself. Maybe lay a box ontop of these words and set its position (since we know where the words are located in the document)

We have tried different implementations, using the setAction method, but it doesnt seem to work properly. The result was in most cases, that we saw out box, but there was no link inside or associated with it. (the cursor didn't change and nothing happend, when i clicked inside the box)

Any help is appreciated.

Chrisi
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    Can you share a PDF with a BaseUrl and one without a BaseUrl with us? Or please explain how you defined the BaseUrl using Adobe's implementation. Or even better: can you point me at the section in ISO-32000-1 where the concept is described? I know the concept of a base Url in HTML, but I don't think I've encountered it in the context of PDF. Once we see it in the specs, we can easily add it to iText. – Bruno Lowagie Jul 04 '14 at 07:21
  • Unfortunately i cant share any of the documents in question with you since they contain confidential information. I added a code example of our Adobe Implementation, but all it does is setting the baseURL property of an JavaScript object as described in this documentation: http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/js_api_reference.pdf – Chrisi Jul 04 '14 at 09:25
  • OK, that looks straight-forward. Depending on the time I have, I'll cook you some examples. One where I create a PDF from scratch introducing a BaseURL. Another one where I adapt an existing PDF. – Bruno Lowagie Jul 04 '14 at 09:53
  • I've already done some experimenting, but I have a meeting in a moment, so I can't publish anything yet. However, I've already found out that setting the baseURL only works when viewing the PDF in Acrobat. In Reader, you get the following exception: *NotAllowedError: Security settings prevent access to this property or method. Doc.baseURL:1:Document-Level:0000000000000000* – Bruno Lowagie Jul 04 '14 at 10:56

1 Answers1

3

I've made you a couple of examples.

First, let's take a look at BaseURL1. In your comment, you referred to JavaScript, so I created a document to which I added a snippet of document-level JavaScript:

writer.addJavaScript("this.baseURL = \"http://itextpdf.com/\";");

This works perfectly in Adobe Acrobat, but when you try this in Adobe Reader, you get the following error:

NotAllowedError: Security settings prevent access to this property or method. Doc.baseURL:1:Document-Level:0000000000000000

This is consistent with the JavaScript reference for Acrobat where it is clearly indicated that special permissions are needed to change the base URL.

So instead of following your suggested path, I consulted ISO-32000-1 (which was what I asked you to do, but... I've beaten you in speed).

I discovered that you can add a URI dictionary to the catalog with a Base entry. So I wrote a second example, BaseURL2, where I add this dictionary to the root dictionary of the PDF:

PdfDictionary uri = new PdfDictionary(PdfName.URI);
uri.put(new PdfName("Base"), new PdfString("http://itextpdf.com/"));
writer.getExtraCatalog().put(PdfName.URI, uri);

Now the BaseURL works in both Acrobat and Reader.

Assuming that you want to add a BaseURL to existing documents, I wrote BaseURL3. In this example, we add the same dictionary to the root dictionary of an existing PDF:

PdfReader reader = new PdfReader(src);
PdfDictionary uri = new PdfDictionary(PdfName.URI);
uri.put(new PdfName("Base"), new PdfString("http://itextpdf.com/"));
reader.getCatalog().put(PdfName.URI, uri);
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
stamper.close();

Using this code, you can change a link that points to "index.php" (base_url.pdf) into a link that points to "http://itextpdf.com/index.php" (base_url_3.pdf).

Now you can replace your Adobe license with a less expensive iTextSharp license ;-)

Bruno Lowagie
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