In your client (the program that will be requesting quotes), add the following to setup a connection to the server:
import zmq
# Create context (allows for socket creation)
context = zmq.Context()
# Create request socket
socket = context.socket(zmq.REQ)
# Connect to localhost:5555, this is the port that the server listens to.
socket.connect("tcp://localhost:5555")
To request data, we'll use the previously created socket to send different strings which act as commands to request different data.
The following line will request a random quote:
socket.send_string("quote")
Once a quote has been requested, recieve and store the quote in the variable "message" with the following line:
message = socket.recv()
It's VERY important that, after recieving ANY message back from the microservice, you first DECODE the message via the following:
message = message.decode()
Add "-f" at the end of the command to request a favorite quote, and add "-nf" to request a non-favorite quote (if no additional arguments are present, the quote will be randomly chosen from a pool including the favorites list and the default list)
# Request a favorite quote
socket.send_string("quote -f")
# Request a non-favorite quote
socket.send_string("quote -nf")
If an error occurs, due to unrecognized arguments or too many arguments being passed, the server will send back a string starting with "Error." and then a description of the error, instead of a quote.
In the event that a quote is requested and no quotes are stored, the server will send back the string "NoQuote - NoAuthor"
To add the most recently retrieved quote to the Favorites list, send the following command:
socket.send_string("fav")
The server will either send back "True" or "False", based on if the favoriting succeeded (e.g., it will send back "False" if it couldn't find the quote, or if a quote hasn't yet been sent). This response can be retrieved with the following line:
message = socket.recv()
To delete the most recently retrieved quote, send the following command:
socket.send_string("del")
The server will either send back "True" or "False", based on if the deletion succeeded (e.g., it will send back "False" if it couldn't find the quote, or if a quote hasn't yet been sent). This response can be retrieved with the following line:
message = socket.recv()
To add a quote, send a command of the following format:
socket.send_string("add QUOTE_CONTENT @ AUTHOR")
Where QUOTE_CONTENT is the actual quote itself, and AUTHOR is the author of the quote. It's important to note that the AUTHOR is optional, BUT you should NOT include the @ if you're not providing an author. E.g., if you're adding the quote "To be, or not to be", but don't want to include the author, you'd send the following command:
socket.send_string("add To be, or not to be")
and if you do want to include the author, you'd send the following command:
socket.send_string("add To be, or not to be @ Shakespeare")
If an error occurred due to the command containing more than one @ (such as if the quote itself contained an @), the server will send back the string "Error. multiple @ symobls in request: REQUEST_STRING", and the quote will not be added.
It's vital that, when ending the microservice, you send the following command:
socket.send_string("Q")
If this is not sent, the socket connection will not close correctly, and the port may not be free the next time you attempt to open the microservice. If the microservice ever crashes, it closes its connection correctly, but I cannot force it to close safely if you end the program yourself without sending "Q". The service will send one final message of "EXIT" before terminating itself.
Below is a sequence diagram for retrieving a quote from the microservice:
And below is another sequence diagram for an arbitrary interaction with the microservice:
