PDF to HTML Go Examples

Complete Go examples for common PDF to HTML tasks. See the Go SDK guide for installation and result handling.

You can run the examples below with the displayed API credentials. Update the input URLs and filenames as needed. Each Go example can be copied and run independently.

Basic examples

Choose file, in-memory, or output-stream handling for the HTML result. Stream examples use a binary file stream as their destination.

The memory variants return UTF-8 bytes. Decode them when your application needs a text string.

Convert a PDF file

Upload an existing logo.pdf file.

Save to a file

package main

import (
    "log"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    err := client.ConvertFileToFile("logo.pdf", "logo.html")
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Keep in memory

package main

import (
    "log"
    "fmt"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    html_bytes, err := client.ConvertFile("logo.pdf") // []byte
    checkError(err)
    fmt.Println(len(html_bytes))
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Write to a stream

package main

import (
    "log"
    "os"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    output_stream, err := os.Create("logo.html")
    checkError(err)
    err = client.ConvertFileToStream("logo.pdf", output_stream)
    closeErr := output_stream.Close()
    checkError(err)
    checkError(closeErr)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Convert a URL

Fetch a PDF from its URL.

Save to a file

package main

import (
    "log"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    err := client.ConvertUrlToFile(
        "https://your-server.com/invoice.pdf", "invoice.html",
    )
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Keep in memory

package main

import (
    "log"
    "fmt"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    html_bytes, err := client.ConvertUrl("https://your-server.com/invoice.pdf") // []byte
    checkError(err)
    fmt.Println(len(html_bytes))
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Write to a stream

package main

import (
    "log"
    "os"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    output_stream, err := os.Create("invoice.html")
    checkError(err)
    err = client.ConvertUrlToStream(
        "https://your-server.com/invoice.pdf", output_stream,
    )
    closeErr := output_stream.Close()
    checkError(err)
    checkError(closeErr)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Convert raw PDF bytes

Read logo.pdf as binary data. In an application, pass the bytes you already hold in memory instead.

Save to a file

package main

import (
    "log"
    "os"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    pdf_data_1, err := os.ReadFile("logo.pdf") // []byte
    checkError(err)
    err = client.ConvertRawDataToFile(pdf_data_1, "logo.html")
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Keep in memory

package main

import (
    "log"
    "os"
    "fmt"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    pdf_data_1, err := os.ReadFile("logo.pdf") // []byte
    checkError(err)
    html_bytes, err := client.ConvertRawData(pdf_data_1) // []byte
    checkError(err)
    fmt.Println(len(html_bytes))
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Write to a stream

package main

import (
    "log"
    "os"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    pdf_data_1, err := os.ReadFile("logo.pdf") // []byte
    checkError(err)
    output_stream, err := os.Create("logo.html")
    checkError(err)
    err = client.ConvertRawDataToStream(pdf_data_1, output_stream)
    closeErr := output_stream.Close()
    checkError(err)
    checkError(closeErr)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Read from an input stream

Open logo.pdf as a binary input stream and save the result to logo.html.

package main

import (
    "log"
    "os"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    input_stream, err := os.Open("logo.pdf")
    checkError(err)
    err = client.ConvertStreamToFile(input_stream, "logo.html")
    closeErr := input_stream.Close()
    checkError(err)
    checkError(closeErr)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Customize the HTML output

These examples upload report.pdf, a document with text, images, and vector graphics.

Convert selected pages

Convert pages 1 and 3 of report.pdf into excerpt.html.

package main

import (
    "log"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    client.SetPrintPageRange("1,3")
    err := client.ConvertFileToFile("report.pdf", "excerpt.html")
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Export HTML with separate assets

Save the HTML, stylesheets, fonts, and images in report.zip. Extract the archive and serve its HTML with the accompanying files, preserving their relative paths.

package main

import (
    "log"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    client.SetCssMode("separate")
    client.SetFontMode("separate")
    client.SetForceZip(true)
    client.SetImageMode("separate")
    err := client.ConvertFileToFile("report.pdf", "report.zip")
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Customize the document preview

Scale pages to 75% and change the background, page spacing, and corners in preview.html. Use !important to override the generated background and margin rules.

package main

import (
    "log"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    client.SetCustomCss(
        "#page-container { background: #eaf0f6 !important; } .page { margin: 24px auto !important; border-radius: 8px; }",
    )
    client.SetScaleFactor(75)
    err := client.ConvertFileToFile("report.pdf", "preview.html")
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Avoid naming conflicts

Prefix generated IDs, CSS classes, and font names with report_ in namespaced.html. This helps avoid naming conflicts when integrating the converted content into another page; adjust the surrounding layout separately.

package main

import (
    "log"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    client.SetHtmlNamespace("report_")
    err := client.ConvertFileToFile("report.pdf", "namespaced.html")
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Reduce image resolution

Render page graphics at 72 DPI instead of the default 144 DPI and save smaller.html. Lower resolution can reduce file size at the cost of image detail; text remains HTML text.

package main

import (
    "log"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    client.SetDpi(72)
    err := client.ConvertFileToFile("report.pdf", "smaller.html")
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

Preserve vector graphics with SVG

Use SVG for page graphics in vector.html, preserving vector shapes when zooming. Raster images in the PDF remain raster images within the SVG.

package main

import (
    "log"
    "github.com/pdfcrowd/pdfcrowd-go"
)

func main() {
    client := pdfcrowd.NewPdfToHtmlClient("demo", "demo")

    client.SetImageFormat("svg")
    err := client.ConvertFileToFile("report.pdf", "vector.html")
    checkError(err)
}

func checkError(err error) {
    if err != nil {
        log.Fatal(err)
    }
}