Consuming HTTP Services in Python Transcripts
Chapter: The service landscape
Lecture: Service type: Raw sockets
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Let's begin our exploration of services and consuming services in Python
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by taking a survey of the various types of services
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that we might encounter out there in the world.
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We are going to do this by focusing on the lowest level services
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and moving up in abstractions.
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So the lowest level service that we could have,
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the way that we could talk to the service
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is with using just raw network sockets and just sending bytes on the wire.
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So we would open up a socket with bidirectional communication
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and we would send 00101 over the service and it knows what that means,
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they will say great, 1101 and so on.
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This is the fastest, lowest level, lowest latency way to interact with services,
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so there are benefits here, it's super fast and it's responsive
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because we can actually send custom messages tailor made
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for the types of messages that these two apps exchange,
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it can be extremely low overhead in terms of bandwidth,
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do you need to send four bytes as an integer?
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Well, maybe you just send four bytes and it just knows an integer is coming,
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so literally, there is no wasted sort of packaging on the messages,
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so why aren't all of our services like this, well,
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there is usually way more drawbacks than there are benefits.
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many time this means there is special protocols, you have some app,
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in order to talk to it you have to use an entirely unique protocol just to speak to that.
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And often those don't have standards around them,
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often those are brittle and just not easy to work with, not easy to get started.
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Another problem is proxies and firewalls, especially firewalls.
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So packet inspecting firewalls really hate letting traffic out of the firewall,
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if it's some sort of binary blob.
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They would much rather see some kind of HTTP traffic
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where they can inspect it and make sure that it's all legit and good.
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Also, these often run on non standard ports
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and there can be problems with firewalls as well.
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There are some platform specific issues you run into as well,
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like just above raw sockets, but still more or less sending raw bytes
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are things like on the Windows platform DCOM or .NET remoting,
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on Java we have RMI, remote method invocation
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and these might be sending like in memory representations of some kind of object
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from one .NET app to a .NET server for example,
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and that means it's extremely fragile and really inaccessible
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to Python or Javascript or other things like that,
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it's like you have to basically have the same technology on both sides.
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And also, if you look at the network traffic, can you make sense of it?
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I can't, not usually anyway, it's very hard to read just binary blobs,
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it's also hard to debug if things go wrong because you cannot read it,
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okay, but we do have low latency, low bandwidth, high speed raw sockets,
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and that is possible of course in Python.
