Python Jumpstart by Building 10 Apps Transcripts
Chapter: App 5: Real-time weather client
Lecture: Making HTTP Requests with requests
0:00 Now that we have installed Requests and Beautiful Soup,
0:03 it's time to use them in our application
0:05 and this step is going to be surprisingly easy
0:09 this is one of the reasons that working with Python is just so super awesome.
0:12 Ok, so you can see on line 23 I've written Requests
0:16 and this is how you get started with Requests,
0:18 but there is an error and there is a red underline,
0:21 but it's the kind the PyCharm can fix,
0:23 and what we need to do of course is import this external module
0:26 so at the top I would type import space requests
0:28 and I will come back down here and I will start typing you know,
0:31 calling methods on it and so on.
0:33 But, in PyCharm you just hit alt enter,
0:35 and you say I would like to import this please
0:37 and it sort of adjust the scroll so that you don't get a jerky feel
0:42 but there is at the top import Request.
0:44 Right, so I encourage you to let PyCharm help you.
0:47 Now we can say get and you can see it takes a URL, some parameters,
0:50 some kwargs, that's keyword arguments,
0:54 all we really need to do for this simple case is just put the url here
0:57 and we'll say the response that comes back is whatever goes there.
1:02 Let's start by making sure that we get
1:04 a good status code from the web server
1:07 we want a response code of 200,
1:09 response code of 404 or 500 not so super awesome,
1:12 so let's just print out the response.status_code.
1:17 And so we get, so again it's asking what is my zip code
1:20 so I'll say it's 01010, which is as we saw a Massachusetts
1:24 go, wait for a second for the web server to respond and 200, perfect.
1:28 So that means we are talking to this web server,
1:31 you saw there is a little delay,
1:33 that is just the web server actually trying to generate the full page, and that's great,
1:37 but what we really want is the HTML.
1:41 So we can come down here and we can just print out response.text,
1:45 now we want the actual HTML so we are going to do response.text
1:49 if it was a json response we could do like json
1:52 and convert it from json into a Python dictionary things like that,
1:56 but what we want is just text,
1:58 and now this is pretty big page so I want just a small portion of the text,
2:01 in Python there is a really cool thing
2:03 you can do to lists and other collections called Slicing,
2:07 so I can say I would like just from the 0th item to let's say the 250th item right,
2:13 so that will give me the first 250 characters
2:15 and whatever came back from web server, let's see what that is.
2:20 And ta-da, we get just the top little bit of the HTML page
2:25 and you can see already perfect, we are getting Brimfield Massachusetts 01010,
2:29 OH! this slicing concept is really powerful,
2:32 and there is a lot of ways to use it,
2:34 I could say I want the 0th to 250th item like this,
2:37 or when you start at the beginning you can omit this,
2:39 you can also say I would like from the 250th item onto the end like this
2:45 or the length if I knew how long it was,
2:47 but we are just going to go back to this basic version here.
2:50 Now, this is not actually the purpose of this method,
2:53 they just print out a few characters,
2:55 remember the name of the method is get HTML from the web
2:57 so we saw that the HTML is already downloaded
3:00 in the response object and it's just the text.
3:03 Beautiful so where we are calling this function
3:06 we should be capturing the HTML
3:08 so you see we are just throwing it away right now,
3:11 we'll say this HTML equals, and we'll have gotten HTML from the web,
3:14 now I don't feel like we need this comment anymore,
3:16 get HTML from the web, to call the function get HTML from the web
3:19 that's the beauty of functions and choosing good names,
3:22 so the next thing we need to d is parse the HTML there is get part,
3:25 this was Requests, there is parse part, that is Beautiful Soup.
3:30 Before we get to Beautiful Soup though,
3:33 this concept of slicing is super important
3:35 and let's take a moment to just explore that further.