How to convert PDF to JSON from uploaded file for PDF to JSON API in C# using Web API

How to convert PDF to JSON from uploaded file in C# with easy ByteScout code samples to make PDF to JSON API. Step-by-step tutorial

In this sample, we’ll observe a program which converts data in PDF to JSON format. For this we’ll use API and for implementation we’ll choose C# programming language.

This coding tutorial is designed to help you understand the features without need to write your own code. Web API was made to help with PDF to JSON API in C#. Web API is 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.

This rich sample source code in C# for Web API includes the number of functions and options you should do calling the API to implement PDF to JSON API. Follow the instruction and copy – paste code for C# into your project’s code editor. Test C# sample code examples whether they respond your needs and requirements for the project. This source code is also available on GitHub repository at this location.

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Let’s review C# source code first and then we’ll do analysis of main code snippets.


<?xml version="1.0" encoding="utf-8"?> <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns=""> <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=, 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>


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


using System; using System.Collections.Generic; using System.IO; using System.Net; using Newtonsoft.Json; using Newtonsoft.Json.Linq; namespace ByteScoutWebApiExample { class Program { // The authentication key (API Key). // Get your own by registering at const String API_KEY = "***********************************"; // Source PDF file const string SourceFile = @".\sample.pdf"; // Comma-separated list of page indices (or ranges) to process. Leave empty for all pages. Example: '0,2-5,7-'. const string Pages = ""; // PDF document password. Leave empty for unprotected documents. const string Password = ""; // Destination JSON file name const string DestinationFile = @".\result.json"; 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); // 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( "{0}", Path.GetFileName(SourceFile))); try { // 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(); string uploadedFileUrl = json["url"].ToString(); // 2. UPLOAD THE FILE TO CLOUD. webClient.Headers.Add("content-type", "application/octet-stream"); webClient.UploadFile(uploadUrl, "PUT", SourceFile); // You can use UploadData() instead if your file is byte[] or Stream webClient.Headers.Remove("content-type"); // 3. CONVERT UPLOADED PDF FILE TO JSON // URL for `PDF To JSON` API call var url = ""; // Prepare requests params as JSON Dictionary<string, object> parameters = new Dictionary<string, object>(); parameters.Add("name", Path.GetFileName(DestinationFile)); parameters.Add("password", Password); parameters.Add("pages", Pages); parameters.Add("url", uploadedFileUrl); // Convert dictionary of params to JSON string jsonPayload = JsonConvert.SerializeObject(parameters); // Execute POST request with JSON payload response = webClient.UploadString(url, jsonPayload); // Parse JSON response json = JObject.Parse(response); if (json["error"].ToObject<bool>() == false) { // Get URL of generated JSON file string resultFileUrl = json["url"].ToString(); // Download JSON file webClient.DownloadFile(resultFileUrl, DestinationFile); Console.WriteLine("Generated JSON file saved as \"{0}\" file.", DestinationFile); } else { Console.WriteLine(json["message"].ToString()); } } else { Console.WriteLine(json["message"].ToString()); } } catch (WebException e) { Console.WriteLine(e.ToString()); } webClient.Dispose(); Console.WriteLine(); Console.WriteLine("Press any key..."); Console.ReadKey(); } } }


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


Output of this source code is like below. Please observe input file and it’s output. API Endpoint

Now that we’ve reviewed source code and also previewed output GIF, let’s focus on PDF to JSON API Endpoint.

Api Endpoint
url URL for input file.
pages This parameter expects page no in comma separated way. For example “0,2-5,7-“.
rect If we want to extract only specific region data, then we can user this parameter. Please provide co-ordinates here. For example, 51.8, 114.8, 235.5, 204.0. We can user PDF Viewer with coordinates to easily select and copy paste coordinates.

Please visit documentations for more parameters and detailed usage information.

As you’ve observed, API key is passed in all request headers. This key is required for authentication of request. You can avail this key by signing up for

// Create standard .NET web client instance
WebClient webClient = new WebClient();

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



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