Upload BASE64 binary file to SharePoint document library - sharepoint

Question

I have been looking for ways to upload BASE64 binary files days and I am stuck.
First of all a do not know how to convert BASE64 binary file to array buffer, blob, ... Everything is about BASE64 string but I have BASE64 binary file.
Do you have any solution?

Answer 1

You need to convert this Base64 string to byte array. C# Programming provide several approaches to do this without trouble. Following Upload large files sample SharePoint Add-in and Convert.FromBase64String(String) Method, both at Microsoft Docs, the final code that meet your requirements will be like this:
//This approach is useful for short files, less than 2Mb:
public void UploadFileContentFromBase64(ClientContext ctx, string libraryName, string fileName, string base64Str)
{
Web web = ctx.Web;
// Ensure that target library exists. Create if it is missing.
if (!LibraryExists(ctx, web, libraryName))
{
CreateLibrary(ctx, web, libraryName);
}
FileCreationInformation newFile = new FileCreationInformation();
// The next line of code causes an exception to be thrown for files larger than 2 MB.
newFile.Content = Convert.FromBase64String(base64Str);
newFile.Url = fileName;
// Get instances to the given library.
List docs = web.Lists.GetByTitle(libraryName);
// Add file to the library.
Microsoft.SharePoint.Client.File uploadFile = docs.RootFolder.Files.Add(newFile);
ctx.Load(uploadFile);
ctx.ExecuteQuery();
}
//This other approach provides you to Upload large files, more than 2Mb:
public void UploadDocumentContentStreamFromBase64(ClientContext ctx, string libraryName, string fileName, string base64Str)
{
Web web = ctx.Web;
// Ensure that the target library exists. Create it if it is missing.
if (!LibraryExists(ctx, web, libraryName))
{
CreateLibrary(ctx, web, libraryName);
}
byte[] fileContent = Convert.FromBase64String(base64Str);
using (MemoryStream memStream = new MemoryStream(fileContent))
{
FileCreationInformation flciNewFile = new FileCreationInformation();
// This is the key difference for the first case - using ContentStream property
flciNewFile.ContentStream = memStream;
flciNewFile.Url = fileName;
flciNewFile.Overwrite = true;
List docs = web.Lists.GetByTitle(libraryName);
Microsoft.SharePoint.Client.File uploadFile = docs.RootFolder.Files.Add(flciNewFile);
ctx.Load(uploadFile);
ctx.ExecuteQuery();
}
}