Convert an HTML document to PDF from raw HTML in Go with Net/HTTP

In this guide, we'll show you how to convert an HTML document to PDF using Go and the Net/HTTP library. Providing the HTML document as raw as a lot of great advantages :

It avoids PDFShift to make a network request to fetch the HTML document.
It allows you to convert HTML documents that are not publicly accessible.
It improves the speed of the conversion

If, on top of that, you can provide the styles and javascript also inline in the document (<style> and <script> tags), it will also drastically reduce the duration of the conversion.

For converting a raw document, we use the same parameter as for the URL, which is the source parameter. All you have to do is provide an HTML document.

Here's an example:

package main

import (
    "bytes"
    "encoding/base64"
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {
    // You can get an API key at https://pdfshift.io
    apiKey := "sk_xxxxxxxxxxxx"

    params := map[string]interface{}{
        "source":            "<html><body><h1>This will be a PDF document</h1><p>This will generate a basic PDF to show how you can add raw HTML</body></html>",
    }

    // Marshal the parameters into JSON
    jsonParams, err := json.Marshal(params)
    if err != nil {
        fmt.Println("Error marshaling JSON:", err)
        return
    }

    // Create a new HTTP client
    client := &http.Client{}

    // Create a new request
    req, err := http.NewRequest("POST", "https://api.pdfshift.io/v3/convert/pdf", bytes.NewBuffer(jsonParams))
    if err != nil {
        fmt.Println("Error creating request:", err)
        return
    }

    // Set request headers
    req.Header.Set("Content-Type", "application/json")

    // Set basic authentication header
    auth := "api:" + apiKey
    req.Header.Set("Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(auth)))

    // Perform the request
    resp, err := client.Do(req)
    if err != nil {
        fmt.Println("Error performing request:", err)
        return
    }
    defer resp.Body.Close()

    // Read response body
    body, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        fmt.Println("Error reading response body:", err)
        return
    }

    // Check response status code
    if resp.StatusCode >= 400 {
        fmt.Printf("Request failed with status code %d: %s\n", resp.StatusCode, string(body))
        return
    }

    // Save the PDF document
    err = ioutil.WriteFile("result.pdf", body, 0644)
    if err != nil {
        fmt.Println("Error saving PDF document:", err)
        return
    }

    fmt.Println("The PDF document was generated and saved to result.pdf")
}

Providing the source parameter as a raw HTML document is by far the best recommended method to convert HTML documents in PDFShift as it reduce the amount of network requests, loading time of each documents (image, css, javascript, etc) and thus improve the conversion time.

For further details on the property and its usage, please refer to our dedicated documentation.

We hope this guide was helpful. If you have any questions or noticed any issues on the code above,
feel free to drop us a line.