kennethreitz/dive-into-python3
1
0
Fork 0
mirror of https://github.com/kennethreitz/dive-into-python3.git synced 2026-06-05 23:10:17 +00:00
Code Issues Packages Projects Releases Wiki Activity

clarifications [h/t boa13]

Browse Source
This commit is contained in:
Mark Pilgrim
2009-06-17 23:48:31 -04:00
parent 4f14392e0e
commit d19ace1879
1 changed files with 3 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files
http-web-services.html
+3 -3
View File
@@ -21,9 +21,9 @@ mark{display:inline}
</blockquote>
<p id=toc>&nbsp;
<h2 id=divingin>Diving In</h2>
<p class=f>HTTP web services are programmatic ways of sending and receiving data from remote servers using nothing but the operations of <abbr>HTTP</abbr>. If you want to get data from the server, use <abbr>HTTP</abbr> <code>GET</code>; if you want to send new data to the server, use <abbr>HTTP</abbr> <code>POST</code>. Some more advanced <abbr>HTTP</abbr> web service <abbr>API</abbr>s also define ways of modifying existing data and deleting data, using <abbr>HTTP</abbr> <code>PUT</code> and <abbr>HTTP</abbr> <code>DELETE</code>. In other words, the &#8220;verbs&#8221; built into the <abbr>HTTP</abbr> protocol (<code>GET</code>, <code>POST</code>, <code>PUT</code>, and <code>DELETE</code>) map directly to application-level operations for retrieving, creating, modifying, and deleting data.
<p class=f>HTTP web services are programmatic ways of sending and receiving data from remote servers using nothing but the operations of <abbr>HTTP</abbr>. If you want to get data from the server, use <abbr>HTTP</abbr> <code>GET</code>; if you want to send new data to the server, use <abbr>HTTP</abbr> <code>POST</code>. Some more advanced <abbr>HTTP</abbr> web service <abbr>API</abbr>s also define ways of creating, modifying, and deleting data, using <abbr>HTTP</abbr> <code>PUT</code> and <abbr>HTTP</abbr> <code>DELETE</code>. In other words, the &#8220;verbs&#8221; built into the <abbr>HTTP</abbr> protocol (<code>GET</code>, <code>POST</code>, <code>PUT</code>, and <code>DELETE</code>) can map directly to application-level operations for retrieving, creating, modifying, and deleting data.
<p>The main advantage of this approach is simplicity, and its simplicity has proven popular. Data &mdash; usually <abbr>XML</abbr> data &mdash; can be built and stored statically, or generated dynamically by a server-side script, and all major programming languages (including Python, of course!) include an <abbr>HTTP</abbr> library for downloading it. Debugging is also easier; because each &#8220;call&#8221; to the web service had a unique <abbr>URL</abbr>, you can load it in your web browser and immediately see the raw data.
<p>The main advantage of this approach is simplicity, and its simplicity has proven popular. Data &mdash; usually <abbr>XML</abbr> data &mdash; can be built and stored statically, or generated dynamically by a server-side script, and all major programming languages (including Python, of course!) include an <abbr>HTTP</abbr> library for downloading it. Debugging is also easier; because each resource in an <abbr>HTTP</abbr> web service has a unique address (in the form of a <abbr>URL</abbr>), you can load it in your web browser and immediately see the raw data.
<p>Examples of <abbr>HTTP</abbr> web services:
<ul>
@@ -52,7 +52,7 @@ mark{display:inline}
<h3 id=caching>Caching</h3>
<p>The most important thing to understand about any type of web service is that network access is incredibly expensive. I don&#8217;t mean &#8220;dollars and cents&#8221; expensive (although bandwidth ain&#8217;t free). I mean that it takes an extraordinary long time to open a connection, send a request, and retrieve a response from a remote server. Even the fastest broadband connection is orders of magnitude slower than your local network, which in turn is orders of magnitude slower than you local disk.
<p>The most important thing to understand about any type of web service is that network access is incredibly expensive. I don&#8217;t mean &#8220;dollars and cents&#8221; expensive (although bandwidth ain&#8217;t free). I mean that it takes an extraordinary long time to open a connection, send a request, and retrieve a response from a remote server. Even the fastest broadband connection slower than your local network, which in turn is slower than your local disk.
<p><abbr>HTTP</abbr> is designed with caching in mind. There is an entire class of devices (called &#8220;caching proxies&#8221;) whose only job is to sit between you and the rest of the world and minimize network access. Your company or <abbr>ISP</abbr> almost certainly maintains caching proxies, even if you&#8217;re unaware of them. They work because caching built into the <abbr>HTTP</abbr> protocol.