2019 Middleware Bot Template
There are two projects included:
One is called the Middlewarebot; it is based on the official Bot Framework v4 EchoBot sample.
This bot has been created using Bot Framework, it shows how to create a simple bot that accepts input from the user and echoes it back.
There has been several elements that contain changes from the standard template:
- Startup.cs
- AdapterWithErrorHandler.cs
- TemplateMiddleware.cs
- TemplateMiddleware2.cs
- TemplateMiddleware3.cs
When you want to add your own middleware, you'll need to know where all the middleware pieces need to be declared. Search in the entire project for TemplateMiddleware3 as an example. You'll notice it appear a few times: Startup.cs and the AdapterWithErrorHander.cs - and sometimes more than once.
The other project is called CounterStateMiddlewareBot.
This projects extends the MiddlewareBot; it adds the ability to maintain user and conversation state by adding elements from this project from the official samples.
In the EchoBot file, you'll see that we've listed 3 different Methods to store the data - they are listed as Method 1, Method 2, and Method 3.
Through these interactions, we'll see how Middleware interacts with your bot, interacts with each other (when there is multiple parts to your Middleware), and saves state, and finally, how you can fine-tune your Middleware to only act in certain instances.
Go to the folder called Statement Management and you'll see four files named ConversationData, CounterData, UserProfile, and CounterState.
ConversationData, CounterData, UserProfile are essentially models that define the data we care about as C# classes. We'll use these models as we keep track of the state of the Bot. As we mentioned, there are 3 different methods to keep track of state in the Bot. The first two add the class CounterData as a property to the official storage class called ConversationData. The third (more complicated) method subclasses BotState to create an analogous class to the official storage classes defined in the Bot framework - ie. ConversationData and UserProfile; this class is called CounterState.
Comment out the contents of all Middleware (if you just pulled the code down from the repo - this should be how it is already preset.) You'll see the normal Echo + counter behavior with each interaction adding one count to the displayed counter. This behavior has been added in EchoBot.cs. TemplateMiddleware and TemplateMiddleware2 are similiar to what we saw in the original MiddlewareBot - uncomment out any lines later to see how it interacts with the rest of the project.
You'll notice the method TranslateMessageActivityAsync. If you look at this method what it is doing is taking the Activity message and then appending to it "+ by Middleware 3". Run the bot - and you'll notice it's affect as you interact with the bot.
If you look at TemplateMiddleware4 and TemplateMiddleware5 - you see there a couple sections commented out. They are specified as Step 1, Step 2, Step 3, and Step 4. Comment them out one by one, and run the project between each time you comment a step.
Finally, notice Experiment 1 and Experiment 2. After you get a handle of what the other parts of the middleware are doing, then comment out Experiment 1 (then run the project) and then comment out Experiment 2 (then run the project again). Type a message in the Bot several times. Notice what is happening, pay very close attention to the counts spit back by the Bot. What happens when you comment out Experiment 1? What happens when you comment out Experiment 2? Important: type a couple messages in the Bot; pay very close attention how the counts jump.
Think through the sequence of the steps of the Bots including the sequence of steps of the Middleware. Think about what gets saved and what doesn't when you comment the Experiment 1 and Experiment 2. Then, if you're looking for the "how" and "why" - take a look at EchoBot.cs, specifically on the method: OnTurnAsync(...) Does that help answer questions about why the top (pre-Bot) portion of the Middleware gets saved?
The other is called StateMiddlewareBot.
It is duplicated from the MiddlewareBot and then added the ability to maintain UserState (similar to what we did with the CounterStateMiddlewareBot). It also contains elements from the project Bot Builder project. Look at the project, StateManagementBot there and look at the StateManagementBot.cs file.
Look in the Middleware folder - TemplateMiddleware and TemplateMiddleware2.cs. The await turnContext.SendActivityAsync($"ABC "); are commented out so these files are mostly inert. You can uncomment these statements to see how it interact with the rest of the Middleware / Bot.
The main meat of the sample is in TemplateMiddleware3.cs. There are 4 experiments. Manage the commenting/uncommenting of code so that you only have 1 experiment running at a time.
Each experiment has instructions on pinning variables in Visual Studio. This will help you see what variables/values are flowing through your code. https://blogs.msdn.microsoft.com/benwilli/2015/04/08/visual-studio-tip-2-pin-your-data-tips/
Uncomment Experiment 1 - run the project. What changed about the sent messages?
Do you notice anything about outputs that are sent? Set a breakpoint before and after await nextSend(); and pay attention the sequence of sent messages as it relates to the await nextSend(); The idea of this is to realize how / when the following code is run:
//WHEN DOES THIS HAPPEN?
turnContext.OnSendActivities(async (newContext, activities, nextSend) =>
{
//wHEN DOES THIS HAPPEN?
await nextSend();
//WHEN DOES THIS HAPPEN?
}
The code for experiment 2 is similar but the code after the await nextSend() has been eliminated.
Uncomment Experiment 2 - remember to re-comment out Experiment 1. Run the project. What changed about the sent messages?
Before we run the next experiment - take a step back. You've pinned the variable, you're noticing that after the TranslateMessageActivityAsync is hit, the string changes. However, when you look at the sent messages, the messages sent originating from the Bot are not being changed.
Now in the previous project, the CounterStateMiddlewareBot we added turnContext.SendActivityAsync(string); in various points in the middleware to send messages to the user. Let's do that again in this experiment - Experiment 3.
Uncomment Experiment 3 - remember to re-comment out Experiment 2. Run the project. What happens? Why did it happen?
After Experiment 3 - if there are any issues, you may need to close the project and Visual Studio and run it again.
Uncomment Experiment 4 - remember to re-comment out Experiment 3. Run the project. What happens to the messages? What gets changed? Why did it change? What was added to the code to create the behavior you see.
-
.NET Core SDK version 2.1
# determine dotnet version dotnet --version
-
In a terminal, navigate to
MiddlewareBot# change into project folder cd # MiddlewareBot
-
Run the bot from a terminal or from Visual Studio, choose option A or B.
A) From a terminal
# run the bot dotnet runB) Or from Visual Studio
- Launch Visual Studio
- File -> Open -> Project/Solution
- Navigate to
MiddlewareBotfolder - Select
MiddlewareBot.csprojfile - Press
F5to run the project
Bot Framework Emulator is a desktop application that allows bot developers to test and debug their bots on localhost or running remotely through a tunnel.
- Install the Bot Framework Emulator version 4.3.0 or greater from here
- Launch Bot Framework Emulator
- File -> Open Bot
- Enter a Bot URL of
http://localhost:3978/api/messages
To learn more about deploying a bot to Azure, see Deploy your bot to Azure for a complete list of deployment instructions.
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