An Open Source FileManagement Component Helps Developing File-required Systems Easier in .NET

Introduction

File Management mentioned in the article is a component implemented in RapidWebDev, which is designed to save the effort on developing file-required systems through its easy APIs and integration with ASP.NET web development, e.g. a product requires attachments and thumbnails in a product management system. You shall have basic impression from the following 4 minutes video on WHAT. Then the article introduces the data model, APIs and ASP.NET web control in detail.

Please click the screenshot of the Flash video below to watch it in the popup window.

Data Model

There are only 2 data tables for file management in RapidWebDev v1.52:

fm_Files: The table is used to store file head information only. The file stream is managed by the implementation of IFileStorageApi in file management component. There is a default implementation to store files in shared path.

fm_FileBindings: The table is used to show the relationship between file and external objects.

Internal APIs

There are only two interfaces for developers usually, IFileManagementApi and IFileBindingApi. The former one is used to manage file information and the latter one is used to manage relationship between files and external objects. In the following code snippet, the article ignores overload methods.

/// <summary>
/// API to manage file information.
/// </summary>
public interface IFileManagementApi
{
    /// <summary>
    /// Save a file.
    /// </summary>
    /// <param name="fileUploadObject">
    /// The file uploading object which should include a readable file stream.
    /// </param>
    /// <returns>returns file head of the saved file.</returns>
    FileHeadObject Save(FileUploadObject fileUploadObject);

    /// <summary>
    /// Delete the file by id.
    /// </summary>
    /// <param name="fileId">The file id.</param>
    void Delete(Guid fileId);

    /// <summary>
    /// Load the file by id.
    /// </summary>
    /// <param name="fileId">The file id.</param>
    /// <returns></returns>
    FileHeadObject Load(Guid fileId);
}

/// <summary>
/// API to manage relationship between files and external objects.
/// </summary>
public interface IFileBindingApi
{
    /// <summary>
    /// Bind the file with id of the external object.
    /// </summary>
    /// <param name="relationshipType"></param>
    /// <param name="externalObjectId"></param>
    /// <param name="fileId"></param>
    void Bind(string relationshipType, Guid externalObjectId, Guid fileId);

    /// <summary>
    /// Unbind the files associated with id of the external object 
    /// in special relationship type.
    /// </summary>
    /// <param name="externalObjectId"></param>
    /// <param name="relationshipType"></param>
    void Unbind(Guid externalObjectId, string relationshipType);

    /// <summary>
    /// Delete all files associated with id of the external object 
    /// in any relationship types 
    /// include both file entities and relationship.
    /// </summary>
    /// <param name="externalObjectId"></param>
    void DeleteBoundFiles(Guid externalObjectId);

    /// <summary>
    /// Get the files bound to id of the external object in special relationship type.
    /// </summary>
    /// <param name="externalObjectId"></param>
    /// <param name="relationshipType"></param>
    /// <returns></returns>
    IEnumerable<FileHeadObject> FindBoundFiles
		(Guid externalObjectId, string relationshipType);
}

ASP.NET Web Control

FileManagementControl is used to manage related files to a business object which locates at \\RapidWebDev.FileManagement\Web\FileManagementControl.cs. The control has the following properties:

A sample code below demonstrates how to use the control:

<My:FileManagementControl ID="ProductAttachments" 
   FileCategory="ProductAttachment" 
   RelationshipType="Attachment" runat="server" />

void ButtonLoad_Click(object sender, EventArgs e)
{
    // load the assocated files with the external object.
    this.ProductAttachments.ExternalObjectId = ??;
}

void ButtonSave_Click(object sender, EventArgs e)
{
    // save the managing files with the external object.
    int associatedFileCount = this.ProductAttachments.AssociatedFileCount;
    this.ProductAttachments.ExternalObjectId = ??;
    this.ProductAttachments.Save();
}

Permission Integration

FileManagement integrates with permission through the interface IPermissionBridge in both HTTP file upload/download handler and FileManagementControl. There are three file operation permissions, Upload, Delete and Download. FileManagementControl renders Upload and Delete depending on whether the user has the related permission. HTTP file upload/download handler does the same. The permission value of file operation follows the format below:

• Upload: FileManagement.{FileCategory}.Upload
• Delete: FileManagement.{FileCategory}.Delete
• Download: FileManagement.{FileCategory}.Download

/// <summary>
/// The bridge which is used by RapidWebDev infrastructure for authorization.
/// </summary>
interface IPermissionBridge
{
    /// <summary>
    /// Returns true if the current user has any permissions in specified permission.
    /// </summary>
    /// <param name="permissionValue">Permission value.</param>
    /// <returns>
    /// Returns true if the current user has any permissions in specified permission.
    /// </returns>
    bool HasPermission(string permissionValue);
}   

What's RapidWebDev

Official Website for download: http://www.rapidwebdev.org

RapidWebDev is an infrastructure helps engineers to develop enterprise software solutions in Microsoft .NET easily and productively. It consists of an extendable and maintainable web system architecture with a suite of generic business model, APIs and services as fundamental functionalities needed in development for almost all business solutions. So when engineers develop solutions in RapidWebDev, they can have a lot of reusable and ready things then they can more focus on business logics implementation. In practice, we can save more than 50% time on developing a high quality and performance business solution than direct ASP.NET coding.