1. HTTP Header The HTTP protocol is an application-layer specification built on top of TCP/IP, transmitted as ASCII text. The HTTP specification divides an HTTP request into three parts: the status line, the request headers, and the message body. Something like this: 1 2 3 4 5 <method><request-URL><version> <headers> <entity-body> An HTTP header falls into four categories: general headers, request headers, response headers, and entity headers.

1. Function Methods A function is an organized, reusable snippet of code used to implement a single or related piece of functionality. Functions improve an application’s modularity and the reuse rate of code. Python provides many built-in functions, such as print() and str(). At the same time, Python also allows

1. Introduction Jupyter Notebook (formerly IPython notebook) is an interactive notebook that supports running more than 40 programming languages. Jupyter Notebook is in fact a web application that lets you create and share program documents, with support for live code, mathematical equations, visualizations, and Markdown. Its uses include data cleaning

1. Where a Message Queue Fits 1.1 Asynchronous Processing Use case: after a user registers, a registration email and a registration SMS must be sent. With the synchronous approach, system performance (concurrency, throughput, response time) hits a bottleneck. 1.2 Application Decoupling Use case: after a user places an order, the

1. Basic Concepts Workspace: the working area, the project files Index: the staging area, also called the pending-commit area; before a commit enters the repo, all updates are placed in the staging area Local Repository: the local repo, the version repository kept locally; HEAD points at the current development branch