Extract Image Metadata

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Use the image-info endpoint to get metadata describing an image.

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The image-info endpoint is for obtaining metadata describing an image. In this tutorial we illustrate using this endpoint to obtain an image's metadata. We first call the image-info REST endpoint directly using cURL. We then use the DynamicPDF API client libraries to programmatically call the endpoint.

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Required Resources

To complete this tutorial, you must add the Get Image Information (image-info Endpoint) sample to your samples folder in your cloud storage space using the the File Manager. After adding the sample resources, you should see a samples/get-image-info-image-info-endpoint folder containing the resources for this tutorial.

Sample	Sample Folder	Resources
Get Image Information (image-info Endpoint)	samples/get-image-info-image-info-endpoint	dynamicpdfLogo.png

• From the File Manager, download dynamicpdfLogo.png to your local system; here we assume /temp/dynamicpdf-api-samples/get-image-info.

Resource	Cloud/Local
dynamicpdfLogo.png	local

tip

See Sample Resources for instructions on adding sample resources.

Obtaining API Key

This tutorial assumes a valid API key obtained from the DynamicPDF API's Portal. Refer to the following for instructions on getting an API key.

• Apps and API Keys

tip

If you are not familiar with the File Manager or Apps and API Keys, refer to the following tutorial and relevant Users Guide pages.

• Exploring the File Manager and Apps and API Keys
• File Manager
• Apps and API Keys

Make Request Using API

The image-info endpoint is a form post that takes the API key in the header and the image as binary data in the request's body. The following uses cURL to make an HTTP POST request, passing the image as binary data. Note that in the Header we pass the Content-Type as image/png.

curl -X POST "https://api.dpdf.io/v1.0/image-info" 
-H "Authorization: Bearer DP.xxx-api-key-xxx" 
-H  "Content-Type: image/png" 
--data-binary "@c:/temp/dynamicpdf-api-samples/get-image-info/dynamicpdflogo.png"

Examine API Response

The REST call returns the following JSON describing the image.

[
  {
    "pageNumber": 1,
    "width": 262,
    "height": 250,
    "horizondalDpi": 300,
    "verticalDpi": 300,
    "numberOfComponents": 3,
    "bitsPerComponent": 8,
    "colorSpace": "indexed"
  }
]

info

The JSON response returns an array so that the endpoint can support multi-page tiffs. Refer to the Users Guide for an example using a multi-page tiff image.

Make Request Using Client Library

Now let's use the a client library to call the REST endpoint. To simplify your development, you can use any of the DynamicPDF API client libraries to complete this tutorial section. Each client library tab contains tutorial steps particular to the selected language.

Complete Source

You can access the complete source for this project at one of the following GitHub projects.

Language	File Name	Location (package/namespace/etc.)	GitHub Project
Java	GetImageInfo.java	com.dynamicpdf.api.examples	https://github.com/dynamicpdf-api/java-client-examples
C#	Program.cs	GetImageInfo	https://github.com/dynamicpdf-api/dotnet-client-examples
Nodejs	GetImageInfo.js	nodejs-client-examples	https://github.com/dynamicpdf-api/nodejs-client-examples
PHP	GetImageInfo.php	php-client-examples	https://github.com/dynamicpdf-api/nodejs-client-examples
GO	image-info-example.go	go-client-examples	https://github.com/dynamicpdf-api/go-client-examples/tree/main
Python	ImageInfoExample.py	python-client-examples	https://github.com/dynamicpdf-api/python-client-examples

tip

Click on the language tab of choice to view the tutorial steps for the particular language.

C# (.NET)

Available on NuGet:

Install-Package DynamicPDF.API

• Create a new Console App (.NET Core) project named GetImageInfo.
• Add the DynamicPDF.API NuGet package.
• Create a new static method named Run.
• Add a new ImageResource instance and pass the path to the image in the constructor.
• Create a new ImageInfo instance and pass the ImageResource instance to the constructor.
• Add a call to the ImageInfo instance's Process method and return the response.
• Check that the call was successful and print the image metadata as JSON to the console.
• Run the application and the JSON image metadata appears in the console.

using DynamicPDF.Api;
using System;

namespace GetImageInfo
{
    class Program
    {
        static void Main(string[] args)
        {
            Run("DP.xxx-api-key-xxx", "c:/temp/dynamicpdf-api-samples/get-image-info/");
        }

        public static void Run(String apiKey, String basePath)
        {
            ImageResource imageResource = new ImageResource(basePath + "dynamicpdflogo.png");
            ImageInfo imageInfo = new ImageInfo(imageResource);
            imageInfo.ApiKey = apiKey;
            ImageResponse response = imageInfo.Process();

            if(response.IsSuccessful)
            {
                Console.WriteLine(response.JsonContent);
            } else
            {
                Console.WriteLine(response.ErrorJson);
            }
        }
    }
}

Java

Available on NPM:

npm i @dynamicpdf/api

• Use npm to install the DynamicPDF API module.
• Create a new class named GetImageInfo.
• Create a static Run method.
• Add a new ImageResource instance and pass the path to the image in the constructor.
• Create a new ImageInfo instance and pass the ImageResource instance to the constructor.
• Add a call to the ImageInfo instance's process method and return the response.
• Check that the call was successful and print the image metadata as JSON to the console.
• Add a call to the GetImageInfo.Run() method.

import {
    ImageResource,
    ImageInfo,
    ImageResponse
} from "@dynamicpdf/api"

export class GetImageInfo {
    static async Run() {
        
        var imageResource = new ImageResource("C:/temp/dynamicpdf-api-samples/get-image-info/dynamicpdfLogo.png");
        var imageInfo = new ImageInfo(imageResource); 
        imageInfo.apiKey = "DP.xxx-api-key-xxx";

        var imageResponse = await imageInfo.process();

        if (imageResponse.isSuccessful) {
            console.log(JSON.parse(imageResponse.content));
        } else {
            console.log(imageResponse.errorJson);
        }
    }
}
await GetImageInfo.Run();

• Run the application node ImageInfo.js and the image metadata prints to the console.

Node.js

Available on Maven:

https://search.maven.org/search?q=g:com.dynamicpdf.api

<dependency>
<groupId>com.dynamicpdf.api</groupId>
<artifactId>dynamicpdf-api</artifactId>
<version>1.0.0</version>
</dependency>

• Create a new Maven project and add the DynamicPDF API as a dependency

• Create a new class named GetImageInfo with a main method.

• Create a new static method named Run.

• Add a new ImageResource instance and pass the path to the image in the constructor.

• Create a new ImageInfo instance and pass the ImageResource instance to the constructor.

• Add a call to the ImageInfo instance's Process method and return the response.

• Check that the call was successful and print the image metadata as JSON to the console.

package com.dynamicpdf.api.examples;

import com.dynamicpdf.api.ImageInfo;
import com.dynamicpdf.api.ImageResource;
import com.dynamicpdf.api.ImageResponse;

public class GetImageInfo {
	
	public static void main(String[] args) {
		GetImageInfo.Run("DP.xxx-api-key-xxx",
				"C:/temp/dynamicpdf-api-samples/get-image-info/");

	}

	public static void Run(String key, String basePath) {
		
        ImageResource imageResource = null;
        imageResource = new ImageResource(basePath + "/dynamicpdflogo.png");
        ImageInfo imageInfo = new ImageInfo(imageResource);
        imageInfo.setApiKey(key);
        ImageResponse response = imageInfo.process();

        if(response.getIsSuccessful()) {
            System.out.println(response.getJsonContent());
        } else {
        	System.out.println(response.getErrorJson());
        }
	} 	
}

PHP

Available as a Composer package:

composer require dynamicpdf/api

• Use composer to ensure you have the required PHP libraries.
• Create a new class named GetImageInfo.
• Add a Run method.
• Add a new ImageResource instance and pass the path to the image in the constructor.
• Create a new ImageInfo instance and pass the ImageResource instance to the constructor.
• Add a call to the ImageInfo instance's Process method and return the response.
• Check that the call was successful and print the image metadata as JSON to the console.

<?php

require __DIR__ . '/vendor/autoload.php';

use DynamicPDF\Api\ImageResource;
use DynamicPDF\Api\ImageInfo;

class GetImageInfo
{
    private static string $BasePath = "C:/temp/dynamicpdf-api-samples/get-image-info/";

    public static function Run()
    {
        $imageResource = new ImageResource(GetImageInfo::$BasePath . "dynamicpdfLogo.png");
        $imageInfo = new ImageInfo($imageResource);
        $imageInfo->ApiKey = "DP.xxx-api-key-xxx";
        $response = $imageInfo->Process();

        if($response->IsSuccessful)
        {
            echo ($response->JsonContent);
        } else {
            echo("Error: ");
            echo($response->StatusCode);
            echo($response->ErrorMessage);
        }
    }
}
GetImageInfo::Run();

• Run the application php GetImageInfo.php and the image JSON metadata prints to the console.

GO

Available a GO package: https://pkg.go.dev/github.com/dynamicpdf-api/go-client

• Ensure you have the required GO libraries.
• Create a new file named image-info-example.go.
• Add a main method.
• Add a new ImageResource instance and pass the path to the image in the constructor.
• Create a new ImageInfo instance and pass the ImageResource instance to the constructor.
• Add a call to the ImageInfo instance's Process method and return the response.
• Check that the call was successful and print the image metadata as JSON to the console.
• Run the application go run image-info-example.go and the image JSON metadata prints to the console.

package main

import (
	"fmt"
	"github.com/dynamicpdf-api/go-client/endpoint"
	"github.com/dynamicpdf-api/go-client/resource"
)

func main() {
    basePath := "C:/temp/dynamicpdf-api-samples/"
	resource := resource.NewImageResourceWithResourcePath(basePath+"dynamicpdfLogo.png", "")
	imageInfo := endpoint.NewImageInfo(resource)

	imageInfo.Endpoint.BaseUrl = "https://api.dpdf.io/"
	imageInfo.Endpoint.ApiKey = "DP.xxx-api-key-xxx"

	resp := imageInfo.Process()
	res := <-resp

	if res.IsSuccessful() == true {
		fmt.Print(string(res.Content().Bytes()))
	}
}

Python

Available at: pip install dynamicpdf-api

• Ensure you have the required Python libraries.
• Create a new file named ImageInfoExample.py.
• Add a run method.
• Add a new ImageResource instance and pass the path to the image in the constructor.
• Create a new ImageInfo instance and pass the ImageResource instance to the constructor.
• Add a call to the ImageInfo instance's process method and return the response.
• Check that the call was successful and print the image metadata as JSON to the console.
• Run the application python ImageInfoExample.py and the image JSON metadata prints to the console.

from dynamicpdf_api.image_resource import ImageResource
from dynamicpdf_api.image_info import ImageInfo
import pprint
import json

def run(api_key, basePath):
    resource = ImageResource(basePath + "dynamicpdfLogo.png")
    image_info = ImageInfo(resource)
    image_info.api_key = api_key
    response = image_info.process() 
    print(response.json_content)

if __name__ == "__main__":
    api_key = 'DP.xxx-api-key-xxx'
    basePath = "C:/temp/dynamicpdf-api-samples/"
    run(api_key, basePath)

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In all six languages, the steps were similar. First, we created a new ImageResource instance by loading the path to the image via the constructor. Next, we created a new instance of the ImageInfo class, which abstracts the image-info endpoint. Then the ImageInfo instance prints the extracted image information as JSON after processing. Finally, we called the Process method and print the resultant JSON to the console.

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