PDF to Image / Golang Guide

Overview

This page serves as a guide for using the PDFCrowd API to convert PDF into images in Golang applications.

Installation

Clone pdfcrowd-go from Github into your project source folder: 
git clone https://github.com/pdfcrowd/pdfcrowd-go src/github.com/pdfcrowd/pdfcrowd-go
  1. Download pdfcrowd-6.4.0-go.zip.
  2. Import pdfcrowd.go in your code using its package path.

Quick Start

Below are Golang examples to help you quickly get started with the API. Explore our additional examples for more insights.

For a multi-page PDF, the API returns a ZIP archive containing an image for each page. For a single-page PDF, the output is directly an image (e.g., PNG). To determine the output format, use isZippedOutput(). You can enforce the use of a ZIP archive by using setForceZip(). 

package main

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

func main() {
    // Create an API client instance.
    client := pdfcrowd.NewPdfToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d")

    // If unsure whether the input is a single-page file, enforce ZIP output.
    client.SetOutputFormat("png")
    client.SetForceZip(true)

    // Run the conversion and save the result to a file.
    err := client.ConvertUrlToFile("https://pdfcrowd.com/static/pdf/apisamples/invoice.pdf", "invoice.zip")

    // Check for the conversion error.
    handleError(err)
}

func handleError(err error) {
    if err != nil {
        why, ok := err.(pdfcrowd.Error)
        if ok {
            os.Stderr.WriteString(fmt.Sprintf("Pdfcrowd Error: %s\n", why))
        } else {
            os.Stderr.WriteString(fmt.Sprintf("Generic Error: %s\n", err))
        }

        panic(err.Error())
    }
}
package main

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

func readFile(fileName string) []byte {
    content, err := ioutil.ReadFile(fileName)
    handleError(err)
    return content
}

func main() {
    // Create an API client instance.
    client := pdfcrowd.NewPdfToImageClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d")

    // If unsure whether the input is a single-page file, enforce ZIP output.
    client.SetOutputFormat("png")
    client.SetForceZip(true)

    // Run the conversion and save the result to a file.
    err := client.ConvertRawDataToFile(readFile("/path/to/hello_world.pdf"), "invoice.zip")

    // Check for the conversion error.
    handleError(err)
}

func handleError(err error) {
    if err != nil {
        why, ok := err.(pdfcrowd.Error)
        if ok {
            os.Stderr.WriteString(fmt.Sprintf("Pdfcrowd Error: %s\n", why))
        } else {
            os.Stderr.WriteString(fmt.Sprintf("Generic Error: %s\n", err))
        }

        panic(err.Error())
    }
}

Authentication

To access the API, you will need to use your PDFCrowd username and API key. For initial testing, you may use the following demo credentials without registering:

  • Username: demo
  • API key: ce544b6ea52a5621fb9d55f8b542d14d

To obtain your personal API credentials, start a free trial or purchase the API license.

Error Handling

It is recommended that you implement error handling to catch errors the API may return. Effective error handling is vital as it ensures application stability and provides clearer diagnostics. See the example code below for guidance on implementing error handling, and refer to this list of status codes for more information. 

// call the API 

    // print the error
    os.Stderr.WriteString(fmt.Sprintf("Pdfcrowd Error: %s\n", why))

    // print the error code
    os.Stderr.WriteString(fmt.Sprintf("Pdfcrowd Error Code: %v\n", why.getCode()))

    // print the error message
    os.Stderr.WriteString(fmt.Sprintf("Pdfcrowd Error Message: %v\n", why.getMessage()))

Troubleshooting

  • If you are receiving an error, refer to the API Status Codes for more information.
  • Use setDebugLog() and getDebugLogUrl() to obtain detailed information about the conversion process, including load errors, load times, browser console output, etc.
  • Consult the FAQ for answers to common questions.
  • Contact us if you need assistance or if there is a feature you are missing.

API Method Reference

Refer to the PDF to Image Golang Reference for a description of all API methods.