This project helps you serve web sites/apps with VB6. It is a work in progress. It will eventually become a DLL, but for now it is an EXE project while under development.
It includes a number of nice features to make it easier to deliver websites such as:
VBML files are just HTML files with special comments. The app server will detect the comments and raise an event to your app, which can then respond with HTML that will replace the VBML comment. VBML comments are formatted like this:
Your app will receive "my_vbml_command" in the ConvertVbmlToHtml event, where it can set the p_Html property to whatever you'd like to replace the comment with. VBML commands can also include parameters:
The parameters will be passed in the po_VbmlParameters arraylist in the ConvertVbmlToHtml event, and you can use them however you like. Take a look at the Web/index.vbml file for examples of some VBML comments/commands, then look at the CApp class' mo_VbmlHelper_ConvertVbmlToHtml event sub to see how the VBML commands are processed.
To try it out yourself:
You should see the following page:
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Note that when running in the IDE, the server will be running as a single thread so performance won't be spectacular as each request will have to wait for the previous request to complete. You can however compile the EXE and use the /spawn switch to spawn as many app server listeners as you like. You can then put Nginx in front of the app server and configure it to be a reverse proxy to all your app server listeners.
Here's the code that produces the dynamic portions of the demo page:
You can see it's pretty standard VB6 code, reasonably readable/understandable and concise (62 lines not including comments).
Command Line Parameters
If you compile the EXE you'll have access to some command line parameters:
/spawn <number>
Start the app server in "spawner" mode which will cause it to launch <number> processes in "listener" mode.
/stop
Stop all listener and spawner processes.
/ip <IPv4 address>
Tells the app server what IP to listen on
/port <Port>
Tells the app server what Port to listen on. When used with /spawn, this will be the first port of the first spawned listener. Additonally spawned listeners will listen on <port+spawncount>. For example, spawning 3 listeners at base port 8080 will result in listeners on ports 8080, 8081, and 8082.
/rootpath <folder path>
Tells the server where the web root folder is (for serving files). This defaults to the "application folder\web" folder. All of your static files should be placed in this folder (or subfolders thereof).
It's recommended to start in spawner mode like this:
The above command would spawn 10 app listeners using ports 8080-8089.
Note that the compiled EXE expects the RC6 DLLs to be in the App.Path & "\System" folder for reg-free use.
Anyway, I hope some of you find this useful, and I'll be happy to answer any questions you might have.
SOURCE CODE HERE: VBWebAppServer.zip
It includes a number of nice features to make it easier to deliver websites such as:
- Auto-serves static files (this can be disabled if you want to perform your own file serving).
- Automatically handle If-None-Match headers to return 304 Not Modified when appropriate to save bandwidth.
- Easily handle cookies with the CHttpCookies class.
- Easily handle requests via the CHttpRequest class.
- Easily respond to requests using the CHttpResponse class.
- Include "helper" classes for things like handling dates, encoding HTML entities, "Safe" DB creation, regular expressions, and HTML templates (I call these VBML files, and they have a ".vbml" extension.
- MIME type detection (file extension based).
VBML files are just HTML files with special comments. The app server will detect the comments and raise an event to your app, which can then respond with HTML that will replace the VBML comment. VBML comments are formatted like this:
Code:
<!-- vbml: my_vbml_command -->Code:
<!-- vbml: my_vbmlcommand(2, "Param") -->To try it out yourself:
- Make sure that all the RC6 DLLs are installed on your computer.
- Open VBWebAppServer.vbp and run it.
- In your browser, visit http://127.0.0.1:8080
You should see the following page:
Note that when running in the IDE, the server will be running as a single thread so performance won't be spectacular as each request will have to wait for the previous request to complete. You can however compile the EXE and use the /spawn switch to spawn as many app server listeners as you like. You can then put Nginx in front of the app server and configure it to be a reverse proxy to all your app server listeners.
Here's the code that produces the dynamic portions of the demo page:
Code:
Option Explicit
Private WithEvents mo_VbmlHelper As CAppHelperVbml
Public Sub RespondToRequest(po_Req As CHttpRequest, po_Response As CHttpResponse, po_Helpers As CAppHelpers)
Dim l_VisitCount As Long
With po_Req.Cookies
l_VisitCount = .CookieValueByKeyOrDefaultValue("visitcount", 0)
l_VisitCount = l_VisitCount + 1
.AddOrReplaceCookie "visitcount", l_VisitCount, , , Now + 10000
End With
With po_Response
If po_Helpers.Regex.Test(po_Req.Url(urlsection_Path), "^showcase/[0-9]+$", False) Then
' Get requested showcase image from database by numeric id
With New_C.Connection(pathApp & "web.sqlite", DBOpenFromFile)
With .CreateSelectCommand("SELECT image, etag, extension FROM showcase WHERE id=?")
.SetInt32 1, Split(po_Req.Url(urlsection_Path), "/")(1) ' Get image ID from request and use it for SELECT query
With .Execute(True)
If .RecordCount = 0 Then
' No image found!
po_Response.Send404NotFound
Else
' Found an image. Check to see if requester has a cached copy
If po_Req.Headers.HeaderValue("If-None-Match") = .Fields("etag").Value Then
' Requester has a cached copy, send 304 Not Modified to save bandwidth
po_Response.Send304NotModified
Else
' Requester does not have a cached copy of the image, so send it (along with the ETag so future cache hits can be tested).
po_Response.AddHttpHeader "ETag", .Fields("etag").Value
po_Response.SendSimpleByteArrayResponse .Fields("image").Value, , , mimeTypeFromFilePath(.Fields("extension").Value)
End If
End If
End With
End With
End With
Else
If Not New_C.FSO.FileExists(po_Req.LocalPath) Then
' File Not found!
.Send404NotFound
Else
If LCase$(Right$(po_Req.Url(urlsection_Path), 5)) = ".vbml" Then
' Request for a dynamic .vbml page
Set mo_VbmlHelper = po_Helpers.Vbml ' Pass VBML helper to module level variable to receive events.
.SendSimpleHtmlResponse mo_VbmlHelper.ParseVbmlString(New_C.FSO.ReadTextContent(po_Req.LocalPath)), po_Req.Cookies
Else
' Since we have auto serve enabled, we should never get here
' as the auto-serve feature should have found and served the requested file.
Debug.Assert False
.Send400BadRequest
End If
End If
End If
End With
End Sub
Private Sub mo_VbmlHelper_ConvertVbmlToHtml(ByVal p_VbmlCommand As String, ByVal po_VbmlParameters As RC6.cArrayList, p_Html As String, p_ShouldEscapeHtml As e_HtmlEscapeType)
Dim l_Date As Date
Dim l_ShowcaseCount As Long
Select Case p_VbmlCommand
Case "get_rc6_version"
' Get the file version of RC6.dll for reporting the most recent version
p_Html = New_C.Version
Case "get_rc6_date"
' Get the file creation date of RC6 DLL for reporting the most date of the most recent release
New_C.FSO.GetFileAttributesEx pathSystem & "RC6.dll", , , , l_Date
p_Html = Format$(l_Date, "YYYY-MM-DD")
Case "get_copyright"
' Get the copyright text for the page
p_Html = "Copyright " & Year(Now) & " — Olaf Schmidt."
p_ShouldEscapeHtml = htmlescape_No
Case "get_random_showcase_items"
' Get random RC6 showcase items and build the product showcase card.
' You can pass a count parameter with this command to determine the number of random showcase items to retrieve
l_ShowcaseCount = 2 ' Default to 2 showcase items
If po_VbmlParameters.Count > 0 Then l_ShowcaseCount = po_VbmlParameters.Item(0) ' Get the desired # of showcase items if defined.
With New_C.Connection(pathApp & "web.sqlite", DBOpenFromFile)
With .OpenRecordset("SELECT rowid, product_name, developer, description_html, website FROM showcase ORDER BY random() LIMIT " & l_ShowcaseCount)
Do Until .EOF
p_Html = p_Html & "<div class='card p-4'>" & _
"<h2 class='text-center'>" & htmlEscape(.Fields("product_name")) & "<br>by " & htmlEscape(.Fields("developer")) & "</h2>" & _
"<img alt='" & htmlEscape(.Fields("product_name")) & " Screenshot' style='max-height: 150px;' class='img-fluid mt-4 mb-4 mx-auto' src='showcase/" & htmlEscape(.Fields("id")) & "' />" & _
.Fields("description_html") & _
"<p><a href='" & htmlEscape(.Fields("website")) & "'>Learn more about " & htmlEscape(.Fields("product_name")) & "...</a></p>" & _
"</div>"
.MoveNext
Loop
End With
End With
p_ShouldEscapeHtml = htmlescape_No
Case Else
p_Html = "Unhandled VBML Command: " & p_VbmlCommand
Debug.Print p_Html
'Debug.Assert False
End Select
End SubCommand Line Parameters
If you compile the EXE you'll have access to some command line parameters:
/spawn <number>
Start the app server in "spawner" mode which will cause it to launch <number> processes in "listener" mode.
/stop
Stop all listener and spawner processes.
/ip <IPv4 address>
Tells the app server what IP to listen on
/port <Port>
Tells the app server what Port to listen on. When used with /spawn, this will be the first port of the first spawned listener. Additonally spawned listeners will listen on <port+spawncount>. For example, spawning 3 listeners at base port 8080 will result in listeners on ports 8080, 8081, and 8082.
/rootpath <folder path>
Tells the server where the web root folder is (for serving files). This defaults to the "application folder\web" folder. All of your static files should be placed in this folder (or subfolders thereof).
It's recommended to start in spawner mode like this:
Code:
VbWebApp.exe /spawn 10 /ip 127.0.0.1 /port 8080Note that the compiled EXE expects the RC6 DLLs to be in the App.Path & "\System" folder for reg-free use.
Anyway, I hope some of you find this useful, and I'll be happy to answer any questions you might have.
SOURCE CODE HERE: VBWebAppServer.zip