Using cookies to convert HTML documents to PDF in Go with Net/HTTP

In this comprehensive guide, we will demonstrate the step-by-step process of incorporating custom Cookies into your URL request for PDF conversion using PDFShift's API. By leveraging this functionality, you can maintain an active session, enabling authentication as a specific user before generating the PDF document.

To do so, we'll use the cookies parameter when sending a request to PDFShift. It expects a list of dictionnary that contains the name and the value of the cookies (more details after):

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": "https://www.example.com",
        // The "cookies" parameter expects a list of dictionnary that contains the name and the value of the cookies
        "cookies": []map[string]string{
            {"name": "PHPSESSID", "value": "el4ukv0kqbvoirg7nkp4dncpk3"},
        },
    }

    // 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")
}

The cookies parameter accept the following parameters:

name : The name of the cookie.
value: The value of the cookie.
secure: A boolean (defaults to false) that will tell the browser to only send the cookie if the request is being sent over HTTPS.
http_only: A boolean (defaults to false) that will tell the browser to not expose it to client-side scripts.

Like in our guide to send custom HTTP headers or to access secured pages, this allows you to protect your documents from any visitors while allowing PDFShift to access the page and convert it to PDF.

For further details on the cookies 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.