How to List Files — OneDrive Connector for C#

Introduction

In this article we will delve deeper into OneDrive and C# integration, and will learn how to list files. We are continuing from where we left off. By this time, you must have created ODBC Data Source and connected to OneDrive. So, let's not waste time and begin.

Use Query Builder to generate SQL query

The first thing you have to do is open Query Builder:

ZappySys API Driver - OneDrive

OneDrive Connector can be used to integrate OneDrive and your defined data source, e.g. Microsoft SQL, Oracle, Excel, Power BI, etc. Get, write, delete OneDrive data in a few clicks!

OnedriveDSN
Then simply select the List Files endpoint (action).
Continue by configuring the Required parameters. You can also set optional parameters too.
Move on by hitting Preview Data button to preview the results.

If you see the results you need, simply copy the generated query:

List Files

Required Parameters
Drive Id / Shared Folder	Select the value from the dropdown
Search Path (Default=Root Folder) - Max 200 listed	Select the value from the dropdown
Optional Parameters
Default Group or User Id (additional Scopes needed to list - If fails enter manually)
Search Type (Default=Recursive)	search(q='')
Order By Field(s) - Only for Recursive SearchType
Advanced Properties
Record Filter (Client Side)	$.value[?(@.file.mimeType != null)]

SELECT * FROM list_files
WITH(
     Filter='$.value[*]' --list both files and folders
   --Filter='$.value[?(@.file.mimeType != null)]' --list only files
   --Filter='$.value[?(@.folder.childCount != null)]' --list only folders
	,DriveId='b!GtLN726LE0eY5F2BBNi14wMKmwdpCDFMn1d71ra11GuQ4DORpHy-Sa5UzSpkaY9E'
  --,SearchPath='/root'	--folder path
  --,SearchPath='/root:/myfolder:'	--folder path
	,SearchPath='/root:/myfolder/subfolder:' --folder path nested
    ,OrderBy='lastModifiedDateTime desc'
)		
--You can get DriveId by selecting from 'Drives' table.
--You can get SearchPath by selecting from 'list_root' table OR selection from 'list_folder'.

That's it! You can use this query in C#.

Let's not stop here and explore SQL query examples, including how to use them in Stored Procedures and Views (virtual tables) in the next steps.

SQL query examples

Use these SQL queries in your C# data source:

How to List files in a folder path (Recursive)

Use list_files endpoint to list files recursivly (list from child folder). However there are some limitations to list recursively, such as some new files may not appear right away or files not indexed wont show up.

SELECT * FROM list_files
WITH(
     Filter='$.value[*]' --list both files and folders
   --Filter='$.value[?(@.file.mimeType != null)]' --list only files
   --Filter='$.value[?(@.folder.childCount != null)]' --list only folders
	,DriveId='b!GtLN726LE0eY5F2BBNi14wMKmwdpCDFMn1d71ra11GuQ4DORpHy-Sa5UzSpkaY9E'
  --,SearchPath='/root'	--folder path
  --,SearchPath='/root:/myfolder:'	--folder path
	,SearchPath='/root:/myfolder/subfolder:' --folder path nested
    ,OrderBy='lastModifiedDateTime desc'
)		
--You can get DriveId by selecting from 'Drives' table.
--You can get SearchPath by selecting from 'list_root' table OR selection from 'list_folder'.

How to List files from Group / other User's drive

This example shows how to read files from Group or other User's drive. You must use SearchType='children' for this purpose (known issue: recursive option may not work correctly in some cases).

SELECT * FROM list_files
WITH(
	  GroupOrUserId='/groups/138eb458-84f0-4928-bbe6-df663bd1fcea'
	, DriveId='b!VxnFPrt3C0GQnQ70Skx-p9_Eqvvac5pGhvqzoRdUpnZb-G5HVC0WTbLU3a89b4LJ'
	, SearchType='children'
	, SearchPath='/root:/folder/subfolder:'
	--, Filter='$.value[*]' --list both files and folders
	--, Filter='$.value[?(@.folder.childCount != null)]' --list only folders
)

How to List All Files (Recursive)

Lists all files (recursive)

SELECT * FROM Files

How to List All Files and Folders (Recursive)

Lists all files and folders recursively

SELECT * FROM FilesFolders

How to List All Folders (Recursive)

Lists all folders recursively (exclude files)

SELECT * FROM Folders

How to List All Files and Folders Shared with Me

Lists all files / folders shared with me. To List shared file inside a specific folder use FilesFolders table (e.g. select * from FilesFolders WITh(DriverId='zzzzz', SearchPath='zzzz') ). Provide DriveId (Found in SharedWithMe Table - see remoteItem_parentReference_driveId column) and optionally supply SearchPath (e.g. /root:/folder/subfolder: ) from which you like to list files/folders.

SELECT * FROM SharedWithMe

list_files endpoint belongs to Files , FilesFolders , Folders , SharedWithMe table(s), and can therefore be used via those table(s).

Stored Procedures and Views

Create Custom Stored Procedure

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 Stored Procedure in ZappySys Driver. You can insert Placeholders anywhere inside Procedure Body. Read more about placeholders here

Go to Custom Objects Tab and Click on Add button and Select Add Procedure:
Enter the desired Procedure name and click on OK:
Select the created Stored Procedure and write the your desired stored procedure and Save it and it will create the custom stored 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>';
```
That's it now go to Preview Tab and Execute your Stored 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';
```
Let's generate the SQL Server Query Code to make the API call using stored 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([LS_TO_ONEDRIVE_IN_GATEWAY], 'EXEC usp_get_orders @fromdate=''1996-07-30''')
```
Now go to SQL served and execute that query and it will make the API call using stored procedure and provide you the response.

Create Custom Virtual Table

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.

If you're dealing with Microsoft Access and need to import data from an SQL query, it's important to note that Access doesn't allow direct import of SQL queries. Instead, you can create custom objects (Virtual Tables) to handle the import process.

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.

Go to Custom Objects Tab and Click on Add button and Select Add Table:
Enter the desired Table name and click on OK:
And it will open the New Query Window Click on Cancel to close that window and go to Custom Objects Tab.
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'
```
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"
```
Let's generate the SQL Server Query Code to make the API call using stored 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([LS_TO_ONEDRIVE_IN_GATEWAY], 'EXEC [usp_get_orders] ''1996-01-01''')
```
Now go to SQL served and execute that query and it will make the API call using stored procedure and provide you the response.

List Files in C#

We are at the point where we can reiterate on how to use the SQL query, Stored Procedures or Views in C#:

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

"OnedriveDSN";
Press F5 to run the code and read the data:

Here is the code in text format:

using System;
using System.Data.Odbc;

namespace ConsoleApp {
    class Program {
        static void Main() {
            var dsn = "OnedriveDSN";
            using (var conn = new OdbcConnection(String.Format("DSN={0}", dsn)))
            {
                conn.Open();
                var cmd = new OdbcCommand("SELECT * FROM Products", conn);
                
                //Increase the timeout duration from the default 30 seconds, which may be insufficient in certain scenarios
                cmd.CommandTimeout=600; // 600-Seconds
                
                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();
        }
    }
}