PDF.co Web API - Barcode Reader API - C# - Async file upload and async barcode reading

printable version:
PDF-co-Web-API-C-sharp-Async-file-upload-and-async-barcode-reading.pdf

barcode reader API in C# using PDF.co Web API

PDF.co Web API: the Rest API that provides set of data extraction functions, tools for documents manipulation, splitting and merging of pdf files. Includes built-in OCR, images recognition, can generate and read barcodes from images, scans and pdf.

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Web API (on-demand version)

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ByteScoutWebApiExample.csproj

      <?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
    <ProjectGuid>{1E1C2C34-017E-4605-AE2B-55EA3313BE51}</ProjectGuid>
    <OutputType>Exe</OutputType>
    <AppDesignerFolder>Properties</AppDesignerFolder>
    <RootNamespace>ByteScoutWebApiExample</RootNamespace>
    <AssemblyName>ByteScoutWebApiExample</AssemblyName>
    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
    <FileAlignment>512</FileAlignment>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <Optimize>false</Optimize>
    <OutputPath>bin\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugType>pdbonly</DebugType>
    <Optimize>true</Optimize>
    <OutputPath>bin\Release\</OutputPath>
    <DefineConstants>TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
      <HintPath>packages\Newtonsoft.Json.10.0.3\lib\net40\Newtonsoft.Json.dll</HintPath>
      <Private>True</Private>
    </Reference>
    <Reference Include="System" />
    <Reference Include="System.Core" />
    <Reference Include="System.Xml.Linq" />
    <Reference Include="System.Data" />
    <Reference Include="System.Xml" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="Program.cs" />
    <Compile Include="Properties\AssemblyInfo.cs" />
  </ItemGroup>
  <ItemGroup>
    <None Include="packages.config" />
    <Content Include="sample.pdf">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </Content>
  </ItemGroup>
  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
       Other similar extension points exist, see Microsoft.Common.targets.
  <Target Name="BeforeBuild">
  </Target>
  <Target Name="AfterBuild">
  </Target>
  -->
</Project>

ByteScoutWebApiExample.sln

      
Microsoft Visual Studio Solution File, Format Version 12.00
# Visual Studio 2013
VisualStudioVersion = 12.0.40629.0
MinimumVisualStudioVersion = 10.0.40219.1
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ByteScoutWebApiExample", "ByteScoutWebApiExample.csproj", "{1E1C2C34-017E-4605-AE2B-55EA3313BE51}"
EndProject
Global
	GlobalSection(SolutionConfigurationPlatforms) = preSolution
		Debug|Any CPU = Debug|Any CPU
		Release|Any CPU = Release|Any CPU
	EndGlobalSection
	GlobalSection(ProjectConfigurationPlatforms) = postSolution
		{1E1C2C34-017E-4605-AE2B-55EA3313BE51}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
		{1E1C2C34-017E-4605-AE2B-55EA3313BE51}.Debug|Any CPU.Build.0 = Debug|Any CPU
		{1E1C2C34-017E-4605-AE2B-55EA3313BE51}.Release|Any CPU.ActiveCfg = Release|Any CPU
		{1E1C2C34-017E-4605-AE2B-55EA3313BE51}.Release|Any CPU.Build.0 = Release|Any CPU
	EndGlobalSection
	GlobalSection(SolutionProperties) = preSolution
		HideSolutionNode = FALSE
	EndGlobalSection
EndGlobal

Program.cs

      using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Threading;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace ByteScoutWebApiExample
{
    class Program
    {
        // The authentication key (API Key).
        // Get your own by registering at https://app.pdf.co/documentation/api
        const String API_KEY = "***********************************";
        
        // Source file
        const string SourceFile = @".\sample.pdf";

        // Comma-separated list of barcode types to decode.
        // See the documentation: https://apidocs.pdf.co/?#barcode-reader
        const string BarcodeTypes = "Code39,Code128,Interleaved2of5,EAN13";
        
        // Comma-separated list of page indices (or ranges) to process. Leave empty for all pages. Example: '0,2-5,7-'.
        const string Pages = "";
        
        // (!) Make asynchronous job
        const bool Async = true;


        static void Main(string[] args)
        {
            // Create standard .NET web client instance
            WebClient webClient = new WebClient();

            // Set API Key
            webClient.Headers.Add("x-api-key", API_KEY);

            // Upload file to the cloud
            string uploadedFileUrl = UploadFile(SourceFile);
            
            if (string.IsNullOrEmpty(uploadedFileUrl))
            {
                Console.WriteLine("File upload error.");
                return;
            }

            // * READ BARCODES FROM UPLOADED FILE *

            // Prepare requests params as JSON
            // See documentation: https://apidocs.pdf.co/?#barcode-reader
            Dictionary<string, string> parameters = new Dictionary<string, string>();
            parameters.Add("url", uploadedFileUrl);
            parameters.Add("type", BarcodeTypes);
            parameters.Add("pages", Pages);
            parameters.Add("async", Async.ToString());
            // Convert dictionary of params to JSON
            string jsonPayload = JsonConvert.SerializeObject(parameters);

            try
            {
                // URL of "Barcode Reader" endpoint
                string url = "https://api.pdf.co/v1/barcode/read/from/url";

                // Execute POST request with JSON payload
                string response = webClient.UploadString(url, jsonPayload);

                // Parse JSON response
                JObject json = JObject.Parse(response);

                if (json["error"].ToObject<bool>() == false)
                {
                    // Asynchronous job ID
                    string jobId = json["jobId"].ToString();
                    // URL of generated JSON file with decoded barcodes that will available after the job completion
                    string resultFileUrl = json["url"].ToString();

                    // Check the job status in a loop. 
                    // If you don't want to pause the main thread you can rework the code 
                    // to use a separate thread for the status checking and completion.
                    do
                    {
                        string status = CheckJobStatus(jobId); // Possible statuses: "working", "failed", "aborted", "success".

                        // Display timestamp and status (for demo purposes)
                        Console.WriteLine(DateTime.Now.ToLongTimeString() + ": " + status);

                        if (status == "success")
                        {
                            // Download JSON results file as string
                            string jsonFileString = webClient.DownloadString(resultFileUrl);

                            JArray jsonFoundBarcodes = JArray.Parse(jsonFileString);

                            // Display found barcodes in console
                            foreach (JToken token in jsonFoundBarcodes)
                            {
                                Console.WriteLine("Found barcode:");
                                Console.WriteLine("  Type: " + token["TypeName"]);
                                Console.WriteLine("  Value: " + token["Value"]);
                                Console.WriteLine("  Document Page Index: " + token["Page"]);
                                Console.WriteLine("  Rectangle: " + token["Rect"]);
                                Console.WriteLine("  Confidence: " + token["Confidence"]);
                                Console.WriteLine();
                            }

                            break;
                        }
                        else if (status == "working")
                        {
                            // Pause for a few seconds
                            Thread.Sleep(3000);
                        }
                        else
                        {
                            Console.WriteLine(status);
                            break;
                        }
                    }
                    while (true);
                }
                else
                {
                    // Display service reported error
                    Console.WriteLine(json["message"].ToString());
                }
            }
            catch (WebException e)
            {
                // Display request error
                Console.WriteLine(e.ToString());
            }
            finally
            {
                webClient.Dispose();
            }


            Console.WriteLine();
            Console.WriteLine("Press any key...");
            Console.ReadKey();
        }

        /// <summary>
        /// Uploads file to the cloud and return URL of uploaded file to use in further API calls.
        /// </summary>
        /// <param name="file">Source file name (path).</param>
        /// <returns>URL of uploaded file</returns>
        static string UploadFile(string file)
        {
            // Create standard .NET web client instance
            WebClient webClient = new WebClient();

            // Set API Key
            webClient.Headers.Add("x-api-key", API_KEY);

            try
            {
                // 1. RETRIEVE THE PRESIGNED URL TO UPLOAD THE FILE.
                // * If you already have a direct file URL, skip to the step 3.

                // Prepare URL for `Get Presigned URL` API call
                string query = Uri.EscapeUriString(string.Format(
                    "https://api.pdf.co/v1/file/upload/get-presigned-url?contenttype=application/octet-stream&name={0}",
                    Path.GetFileName(file)));

                // Execute request
                string response = webClient.DownloadString(query);

                // Parse JSON response
                JObject json = JObject.Parse(response);

                if (json["error"].ToObject<bool>() == false)
                {
                    // Get URL to use for the file upload
                    string uploadUrl = json["presignedUrl"].ToString();
                    // Get URL of uploaded file to use with later API calls
                    string uploadedFileUrl = json["url"].ToString();

                    // 2. UPLOAD THE FILE TO CLOUD.

                    webClient.Headers.Add("content-type", "application/octet-stream");
                    webClient.UploadFile(uploadUrl, "PUT", file); // You can use UploadData() instead if your file is byte[] or Stream

                    return uploadedFileUrl;
                }
                else
                {
                    // Display service reported error
                    Console.WriteLine(json["message"].ToString());
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                throw;
            }
            finally
            {
                webClient.Dispose();
            }

            return null;
        }

        /// <summary>
        /// Check Job Status
        /// </summary>
        static string CheckJobStatus(string jobId)
        {
            using (WebClient webClient = new WebClient())
            {
                // Set API Key
                webClient.Headers.Add("x-api-key", API_KEY);

                string url = "https://api.pdf.co/v1/job/check?jobid=" + jobId;

                string response = webClient.DownloadString(url);
                JObject json = JObject.Parse(response);

                return Convert.ToString(json["status"]);
            }
        }
    }
}

packages.config

      <?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="Newtonsoft.Json" version="10.0.3" targetFramework="net40" />
</packages>

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printable version:
PDF-co-Web-API-C-sharp-Async-file-upload-and-async-barcode-reading.pdf

PDF.co Web API – Barcode Reader API – C# – Async file upload and async barcode reading