C# REST API Connector In this article you will learn how to integrate REST API data to C# (live / bi-directional connection to REST API). REST API Connector can be used to extract and output JSON/XML/CSV/String data coming from REST API web service calls (Web URL).. Using REST API Connector you will be able to connect, read, and write data from within C#. Follow the steps below to see how we would accomplish that. Download  Help File  Buy  Driver mentioned in this article is part of ODBC PowerPack which is a collection of high-performance Drivers for various API data source (i.e. REST API, JSON, XML, CSV, Amazon S3 and many more). Using familiar SQL query language you can make live connections and read/write data from API sources or JSON / XML / CSV Files inside SQL Server (T-SQL) or your favorite Reporting (i.e. Power BI, Tableau, Qlik, SSRS, MicroStrategy, Excel, MS Access), ETL Tools (i.e. Informatica, Talend, Pentaho, SSIS). You can also call our drivers from programming languages such as JAVA, C#, Python, PowerShell etc. If you are new to ODBC and ZappySys ODBC PowerPack then check the following links to get started. ODBC PowerPack - System Requirements and Installation Getting Started - Using ODBC PowerPack ODBC API Driver Help File

See also Connect REST API in SSIS Connect REST API in SQL Server Connect REST API in Power BI Connect REST API in SSRS Connect REST API in Informatica Connect REST API in MS Access Connect REST API in MS Excel Connect REST API in SSAS Connect REST API in Python Connect REST API in JAVA Connect REST API in Tableau Connect REST API in SAP Crystal Reports Connect REST API in Azure Data Factory (ADF) Connect REST API in ODBC

Create ODBC Data Source (DSN) based on ZappySys JSON Driver

If your API is JSON Type and responding the json string response, in that case using ZappySys JSON Driver we can make the JSON API call and parse the json string. Let's configure the API call in the JSON Driver

1. Install ZappySys ODBC PowerPack.

2. Open ODBC Data Sources (x64):
   

3. Create a User Data Source (User DSN) based on ZappySys JSON Driver

   
   
   
   You should create a System DSN (instead of a User DSN) if the client application is launched under a Windows System Account, e.g. as a Windows Service. If the client application is 32-bit (x86) running with a System DSN, use ODBC Data Sources (32-bit) instead of the 64-bit version.

4. Select Url or File and paste the following Url for this example.
   

   NOTE: Here for demo, We are using odata API, but you need to refer your own API documentation and based on that you need to use your own API URL and need to configure connection based on API Authentication type

   https://services.odata.org/V3/Northwind/Northwind.svc/Customers?$format=json

5. Now enter JSONPath expression in Array Filter textbox to extract only specific part of JSON file as below ($.value[*] will get content of value attribute from JSON document. Value attribute is array of JSON documents so we have to use [*] to indicate we want all records of that array)
   

   NOTE: Here, We are using our desired filter, but you need to select your desired filter based on your requirement.

   
   Click on Test Connection button to view whether the Test Connection is SUCCESSFUL or Not.
   $.value[*]
   

6. Once you configured a data source, you can preview data. Hit Preview tab, and use similar settings to preview data:
   

7. Click OK to finish creating the data source

8. That's it; we are done. In a few clicks we configured the call to JSON API using ZappySys JSON Connector.

Create ODBC Data Source (DSN) based on ZappySys XML Driver

In upper section we we check how to make the JSON API call using JSON Driver and parse the json string response. Same way if your API is XML/SOAP Type and responding the xml string response, in that case using ZappySys XML Driver we can make the XML/SOAP API call and parse the xml string. Let's configure the API call in the XML Driver.

1. Install ZappySys ODBC PowerPack.

2. Open ODBC Data Sources (x64):
   

3. Create a User Data Source (User DSN) based on ZappySys XML Driver

   
   
   
   You should create a System DSN (instead of a User DSN) if the client application is launched under a Windows System Account, e.g. as a Windows Service. If the client application is 32-bit (x86) running with a System DSN, use ODBC Data Sources (32-bit) instead of the 64-bit version.

4. Select Url or File and paste the following Url for this example.
   

   NOTE: Here for demo, We are using odata API, but you need to refer your own API documentation and based on that you need to use your own API URL and need to configure connection based on API Authentication type

   https://services.odata.org/V3/Northwind/Northwind.svc/Customers

5. Now enter Path expression in Array Filter textbox to extract only specific part of XML file as below ($.feed.entry[*] will get content of entry attribute from XML document. Entry attribute is array of XML documents so we have to use [*] to indicate we want all records of that array)
   

   NOTE: Here, We are using our desired filter, but you need to select your desired filter based on your requirement.

   
   Click on Test Connection button to view whether the Test Connection is SUCCESSFUL or Not.
   $.feed.entry[*]
   

6. Once you configured a data source, you can preview data. Hit Preview tab, and use similar settings to preview data:
   

7. Click OK to finish creating the data source.

8. That's it; we are done. In a few clicks we configured the call to XML API using ZappySys XML Connector.

Create ODBC Data Source (DSN) based on ZappySys CSV Driver

In upper section we we check how to make the XML/Soap API call using XML Driver and parse the xml string response. Same way if your API is csv Type or want to parse the CSV file data, in that case using ZappySys CSV Driver we can make the API call or read the CSV file data.

1. Install ZappySys ODBC PowerPack.

2. Open ODBC Data Sources (x64):
   

3. Create a User Data Source (User DSN) based on ZappySys XML Driver

   
   
   
   You should create a System DSN (instead of a User DSN) if the client application is launched under a Windows System Account, e.g. as a Windows Service. If the client application is 32-bit (x86) running with a System DSN, use ODBC Data Sources (32-bit) instead of the 64-bit version.

4. Select Url or File.
   

   Read CSV API in C#

   • Paste the following Url. In this example, We are using Zip format CSV File URL, but you need to refer your CSV File/URL.

     https://zappysys.com/downloads/files/test/cust-1.csv.zip
     Click on Test Connection button to view whether the Test Connection is SUCCESSFUL or Not.

   Read CSV File in C#

   • You can use pass single file or multiple file path using wildcard pattern in path and you can use select single file by clicking [...] path button or multiple file using wildcard pattern in path.
     

     Note: If you want to operation with multiple files then use wild card pattern as below
     (when you use wild card pattern in source path then system will treat target path as folder regardless you end with slash)
     
     C:\SSIS\Test\reponse.csv (will read only single reponse.csv file)
     C:\SSIS\Test\j*.csv (all files starting with file name j)
     C:\SSIS\Test\*.csv (all files with .csv Extension and located under folder subfolder)
     

     Click on Test Connection button to view whether the Test Connection is SUCCESSFUL or Not.

5. Once you configured a data source, you can preview data. Hit Preview tab, and use similar settings to preview data:
   

6. Click OK to finish creating the data source

7. That's it; we are done. In a few clicks we configured the read the CSV data using ZappySys CSV Connector.

Read data in C# from the DSN

1. Create a new Console project and use this code to read the data:
   

   "RestapiDSN";

   

2. Press F5 to run the code and read the data:
   

3. Here is the code in text format:

   
   using System;
   using System.Data.Odbc;
   
   namespace ConsoleApp {
       class Program {
           static void Main() {
               var dsn = "RestapiDSN";
               using (var conn = new OdbcConnection(String.Format("DSN={0}", dsn)))
               {
                   conn.Open();
                   var cmd = new OdbcCommand("SELECT * FROM Products", conn);
                   var rdr = cmd.ExecuteReader();
                   while (rdr.Read())
                   {
                       for (int i = 0; i < rdr.FieldCount; i++)
                       {
                               Console.Write("{0}\t", rdr[i]);
                       }
                       Console.WriteLine();
                   }
               }
               Console.ReadKey();
           }
       }
   }
   

4. If you want to avoid being dependent on a DSN and creating multiple DSNs for each platform (x86, x64), then you can use a fully qualified connection string. Simply go to your DSN and copy the Connection String . Then in your C# code, pass the connection string as an argument when calling the OdbcConnection object's constructor, for example:

       
   var connectionString = "DRIVER={ZappySys API Driver};ServiceUrl=https://services.odata.org/V3/Northwind/Northwind.svc;Provider=OData;AuthName=Http;";
   
   using (var conn = new OdbcConnection(connectionString))
   {
       // ...
   }
   

   How to Overcome the Long Connection String Issue

   This issue is typically caused when the connection string includes a long RefreshToken attribute (i.e. RefreshToken=xxxxxxxxxxxx...xxx, especially if it's more than 1,000 characters).

   A good solution is to supply the RefreshToken by a file. Simply copy and paste the RefreshToken into a text file and save it, and then pass that file path in the connection string instead of directly supplying the RefreshToken.

   Here is an example of a connection string that can cause the issue:

   
   var connectionString = "Driver={ZappySys API Driver};RefreshToken=xxxxxxxxxxxx...xxxxxxx;ServiceUrl=...;";
   
   using (var conn = new OdbcConnection(connectionString))
   {
       // ...
   }
   

   Here is an example of a connection string that has resolved the issue by moving the RefreshToken attribute to the file c:\my_refresh_token.txt:

   
   var connectionString = "Driver={ZappySys API Driver};RefreshTokenFile=c:\my_refresh_token.txt;ServiceUrl=...;";
   
   using (connectionString)
   {
       // ...
   }
   

Create Custom Store Procedure in ZappySys Driver

You can create procedures to encapsulate custom logic and then only pass handful parameters rather than long SQL to execute your API call.

Steps to create Custom Store Procedure in ZappySys Driver. You can insert Placeholders anywhere inside Procedure Body. Read more about placeholders here

1. Go to Custom Objects Tab and Click on Add button and Select Add Procedure:
   

2. Enter the desired Procedure name and click on OK:
   

3. Select the created Store Procedure and write the your desired store procedure and Save it and it will create the custom store procedure in the ZappySys Driver:
   Here is an example stored procedure for ZappySys Driver. You can insert Placeholders anywhere inside Procedure Body. Read more about placeholders here
   

   CREATE PROCEDURE [usp_get_orders]
       @fromdate = '<<yyyy-MM-dd,FUN_TODAY>>'
    AS
       SELECT * FROM Orders where OrderDate >= '<@fromdate>';
   

   
   

4. That's it now go to Preview Tab and Execute your Store Procedure using Exec Command. In this example it will extract the orders from the date 1996-01-01:
   

   Exec usp_get_orders '1996-01-01';

   
   

5. Let's generate the SQL Server Query Code to make the API call using store procedure. Go to Code Generator Tab, select language as SQL Server and click on Generate button the generate the code.
   As we already created the linked server for this Data Source, in that you just need to copy the Select Query and need to use the linked server name which we have apply on the place of [MY_API_SERVICE] placeholder.
   

   SELECT * FROM OPENQUERY([MY_API_SERVICE], 'EXEC [usp_get_orders] ''1996-01-01''')

   
   

6. Now go to SQL served and execute that query and it will make the API call using store procedure and provide you the response.
   

Create Custom Virtual Table in ZappySys Driver

ZappySys API Drivers support flexible Query language so you can override Default Properties you configured on Data Source such as URL, Body. This way you don't have to create multiple Data Sources if you like to read data from multiple EndPoints. However not every application support supplying custom SQL to driver so you can only select Table from list returned from driver.

Many applications like MS Access, Informatica Designer wont give you option to specify custom SQL when you import Objects. In such case Virtual Table is very useful. You can create many Virtual Tables on the same Data Source (e.g. If you have 50 URLs with slight variations you can create virtual tables with just URL as Parameter setting.

1. Go to Custom Objects Tab and Click on Add button and Select Add Table:
   

2. Enter the desired Table name and click on OK:
   

3. And it will open the New Query Window Click on Cancel to close that window and go to Custom Objects Tab.

4. Select the created table, Select Text Type AS SQL and write the your desired SQL Query and Save it and it will create the custom table in the ZappySys Driver:
   Here is an example SQL query for ZappySys Driver. You can insert Placeholders also. Read more about placeholders here
   

   SELECT
     "ShipCountry",
     "OrderID",
     "CustomerID",
     "EmployeeID",
     "OrderDate",
     "RequiredDate",
     "ShippedDate",
     "ShipVia",
     "Freight",
     "ShipName",
     "ShipAddress",
     "ShipCity",
     "ShipRegion",
     "ShipPostalCode"
   FROM "Orders"
   Where "ShipCountry"='USA'

   
   

5. That's it now go to Preview Tab and Execute your custom virtual table query. In this example it will extract the orders for the USA Shipping Country only:
   

   SELECT * FROM "vt__usa_orders_only"

   
   

6. Let's generate the SQL Server Query Code to make the API call using store procedure. Go to Code Generator Tab, select language as SQL Server and click on Generate button the generate the code.
   As we already created the linked server for this Data Source, in that you just need to copy the Select Query and need to use the linked server name which we have apply on the place of [MY_API_SERVICE] placeholder.
   

   SELECT * FROM OPENQUERY([MY_API_SERVICE], 'EXEC [usp_get_orders] ''1996-01-01''')

   
   

7. Now go to SQL served and execute that query and it will make the API call using store procedure and provide you the response.
   

Conclusion

In this article we discussed how to connect to REST API in C# and integrate data without any coding. Click here to Download REST API Connector for C# and try yourself see how easy it is. If you still have any question(s) then ask here or simply click on live chat icon below and ask our expert (see bottom-right corner of this page).

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