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PDF

Introduction​

Netuno generates PDF files with support for images, tables, fonts, and more.

Through the PDF resource that allows a low-code abstraction of iTextPDF for the all programming languages supported by Netuno.

The application that comes with Netuno called demo (demonstration application) contains many examples of possible code implementations in various languages, including a demonstration of exporting to PDF through the export-pdf service located at:

  • netuno/apps/demo/server/services/samples/javascript/export-pdf.js

Initialization​

Firstly, you need to create the object that will contain the context of the new document that is being created, by default the page size is A4.

When creating the document, you define where it will be generated.

If nothing is defined, it will be generated in the service's data output, for example:

const pdfDocument = _pdf.newDocument()

To generate a PDF file inside the application's docs folder, you can do it like this:

const pdfDocument = _pdf.newDocument(_app.file("docs/file.pdf").output())

If you are going to generate the document in a new file outside of the Application, for example:

const pdfDocument = _pdf.newDocument(_os.file("/tmp/file.pdf").output())

Or even in the application storage:

const pdfDocument = _pdf.newDocument(_storage.filesystem("server", "file.pdf").output())

By default, the document is created in A4 page format.

Page Format​

To customize the page format, simply indicate it when creating the document.

Creates a new document to output data from the service with pages in letter format:

const pdfDocument = _pdf.newDocument(_pdf.pageSize("letter"))

Creates a new document for a file in the application root with the B3 page format:

const pdfDocument = _pdf.newDocument(_app.file("file.pdf").output(), _pdf.pageSize("B3"))

Creates a new document in the application's storage with the legal page format:

const pdfDocument = _pdf.newDocument(_storage.filesystem("server", "file.pdf").output(), _pdf.pageSize("legal"))

See the documentation on setting page sizes.

PDF documents can be created with a custom page size definition. To do this, use pageSize by passing the value of the page width and height, for example:

_pdf.pageSize(50, 30)

HTTP Header​

To create a service in the REST API that returns a PDF file as data output, you need to add the Content-Type parameter of the HTTP protocol to the header.

Example of how to set content as PDF:

_header.contentType("pdf")

The pdf code is an abbreviation for:

_header.contentType("application/pdf")

Page Break​

To create a new page, areaBreak is used:

pdfDocument.add(
    _pdf.areaBreak()
)

Paragraph​

Add a new paragraph in the document:

pdfDocument.add(
    _pdf.paragraph("My text here...")
        .setFontSize(15)
)

To add a paragraph at a fixed position:

pdfDocument.add(
    pdfDocument.add(
        _pdf.paragraph("My fixed text...")
            .setFixedPosition(100, 500, 200)
            .setFontSize(15)
    )
)

In the code above, in the setFixedPosition method, the first parameter is the X position (100), the second parameter is the Y position (500), and the third parameter is the width (200).

Attention: if Y is set to 0, this means that it is at the bottom of the page, so to go up you need to increase the Y value, the higher the Y value, the more it will appear at the top, but if it is too high, beyond of the page length so it will not be visible.

Documentation with all iText Paragraph object methods.

Font​

To define a native font we can do it as follows:

const helvetica = _pdf.font("helvetica")
const helveticaBold = _pdf.font("helvetica-bold")
const helveticaBoldOblique = _pdf.font("helvetica-boldoblique")
const helveticaOblique = _pdf.font("helvetica-oblique")

To define a customized font, we can use storage:

const viksiScript = _pdf.font(_storage.filesystem("server", "samples/export-pdf", "viksi-script.ttf"), true)

We can also use a file inside the application, as this example shows that the font is inside the fonts folder in the application root:

const roboto = _pdf.font(_app.file("fonts/roboto.ttf"), true)

Or use a file in any path on the system, so in this example the font is inside the fonts folder which is inside the system's temporary files folder:

const roboto = _pdf.font(_os.file("/tmp/fonts/roboto.ttf"), true)

Documentation with all iText Font object methods.

To use the font in texts, the font constant must be passed to the paragraph, like this:

pdfDocument.add(
    _pdf.paragraph("Using bold font.")
        .setFont(helveticaBold)
        .setFontSize(15)
)

Image​

Inserting images into the programmatically generated PDF document is done in this way:

pdfDocument.add(
    _pdf.image(_storage.filesystem("server", "samples/export-pdf", "logo.png"))
        .scaleAbsolute(120, 36)
)

Note that the scaleAbsolute method is very useful for resizing and adjusting the image size.

Alternatively, we can use a file within the application, as in this example:

const imageLogo = _pdf.image(_app.file("public/images/logo.png")

Or use a file in any path on the system, as in this example:

const imageLogo = _pdf.image(_os.file("/tmp/images/pdf-logo.png")

To add an image in a fixed position:

pdfDocument.add(
    imageLogo
        .scaleAbsolute(120, 36)
        .setFixedPosition(100, 500)
)

Since above, in the setFixedPosition method, the first parameter is the X position (100), the second parameter is the Y position (500).

Attention: if Y is set to 0, this means that it is at the bottom of the page, so to go up you need to increase the Y value, the higher the Y value, the more it will appear at the top, but if it is too high, beyond of the page length so it will not be visible.

Documentation with all iText Image object methods.

Table​

It is possible to create tables, which allows you to present a set of data in a more readable way.

The number of columns in the table is defined with the parameter: _pdf.table(numberOfColumns)

In the example below, the numberOfColumns is the number 1, that is, one column.

As we have added two cells in the table, so the second cell goes to the next row.

Repair:

pdfDocument.add(
    _pdf.table(1)
        .addCell(
            _pdf.cell()
                .add(
                    _pdf.paragraph("Person")
                        .setFont(helvetica)
                        .setFontSize(10)
                )
                .setBorder(_pdf.border("solid", 2))
                .setBackgroundColor(_pdf.colorRGB(1, 0, 0))
        )
        .addCell(
            _pdf.cell()
                .add(
                    _pdf.paragraph("Nicole")
                        .setFont(helvetica)
                        .setFontSize(10)
                )
                .setBackgroundColor(_pdf.colorGray(0.5))
        )
)

With the addCell method you can insert the definition of cells with their respective content.

Documentation with all iText Cell object methods.

Close and Save the Document​

The document is only fully saved or generated, only when the close method is called, as follows:

pdfDocument.close()

Where the document is generated is defined at initialization, so it is at document initialization that we define where the final document will be generated, whether it will be in the service's data output (output) or in a file.

Edit File​

You can edit an existing PDF document, for example:

const pdfDocument = _pdf.openDocument(_app.file("file.pdf"))

The final generated document will be sent in the service's data output.

It is very useful to use a PDF as a base, as if it were a template.

Example for editing a document in the application storage:

const pdfDocument = _pdf.openDocument(_storage.filesystem('server', 'file.pdf'))

Uses a document as a base but saves changes to a new PDF file:

const pdfDocument = _pdf.openDocument(
    _app.file("document-base.pdf"),
    _app.file("document-final.pdf")
)

Example using a document in storage as a base but saving it in another:

const pdfDocument = _pdf.openDocument(
    _storage.filesystem("server", "agreement-base.pdf"),
    _storage.filesystem("server", "agreement-final.pdf")
)

With the document loaded, we can add content, and when closing with the close method at the end, the final document is generated with the new content added programmatically.

Example of a service that uses an existing PDF as a template to generate a PDF file output with dynamic content added:

_header.contentType("pdf")

const pdfDocument = _pdf.openDocument(_app.file("template-1.pdf"))

pdfDocument.add(
    _pdf.paragraph("My dynamic content.")
        .setFixedPosition(37, 730, 100)
        .setFontSize(15)
)

pdfDocument.close()

Read File​

To read a PDF document, extracting the text information.

We use the extract method, which obtains all the data from the PDF file in a JSON object.

const pdfData = _pdf.extract(_app.file("file-1.pdf"))

_out.json(pdfData)

The returned JSON has the key content with all the text content of the PDF file, and has the key metadata with the various properties of the PDF file.

Here is an example of the JSON returned by extract:

{
  "content": "All text content of the PDF file goes here...",
  "metadata":{
    "Content-Type":"application/pdf",
    "dc:format":"application/pdf; version=1.4",
    "dc:title":"Linux 1",
    "pdf:PDFVersion":"1.4",
    "pdf:charsPerPage":"580",
    "pdf:containsDamagedFont":"false",
    "pdf:containsNonEmbeddedFont":"false",
    "pdf:docinfo:producer":"Skia/PDF m125 Google Docs Renderer",
    "pdf:docinfo:title":"File 1",
    "pdf:encrypted":"false",
    "xmpTPg:NPages":"3",
    ...
  }
}

There are many other data that are obtained in the metadata but that were omitted in the ... so the example does not become too long.

Conversion​

It is possible to programmatically convert PDF to text or even HTML.

Text​

We can extract the entire content of the PDF file in plain text using the method:

_pdf.toText(...)

Example of how to use it to read a file in the application root:

_out.print(_pdf.toText(_app.file("my-document.pdf")))

Or using a file in the application's storage:

_out.print(_pdf.toText(_storage.filesystem("server", "my-document.pdf")))

HTML​

We can extract the entire content of the PDF file into HTML using the method:

_pdf.toHTML(...)

Example of how to use it to read a file in the application root:

_out.print(_pdf.toHTML(_app.file("my-document.pdf")))

Or using a file in the application's storage:

_out.print(_pdf.toHTML(_storage.filesystem("server", "my-document.pdf")))