Add slides for HTTP Get requests and query params

units/03 - Introduction to Flask/Introduction to Flask Slides.md

@@ -835,8 +835,6 @@ This is an anchor to a section in the webpage returned by the web server. This i
 
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-<!-- _footer: 'Unit 3: Introduction to Flask (image source: https://developer.mozilla.org/en-US/docs/Learn/Common_questions/Web_mechanics/What_is_a_URL' -->
-
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@@ -980,3 +978,153 @@ You can use both absolute and relative URLs in anchor tags.
 ```
 
 ---
+
+#### Query Parameters and Request Class In Flask
+
+<span class="center wide">
+<img src="assets/Flask Header.png" />
+</span>
+
+---
+
+#### A Quick Review of URL's And Schemes
+
+<span class="centered">
+<img src="assets/Example Url.png" />
+</span>
+
+---
+
+#### What Is HTTP/HTTPS?
+
+<span class="centered">
+<img src="assets/HTTP Request Example.png" />
+</span>
+
+---
+
+#### Website Speak In HTTP
+
+<span class="centered">
+<img src="assets/Website Traffic.png" />
+</span>
+
+---
+
+#### In Flask, We Access HTTP Requests With The `request` Class
+
+`http://127.0.0.1:5000/hello?name=Brady`
+
+```python
+from flask import Flask, request
+
+app = Flask(__name__)
+
+@app.route('/hello') 
+def hello():     
+	name = request.args.get('name')     
+	return "Hello, " + name
+
+app.run()
+```
+
+**Notice that request.args is a dictionary! Remember those?**
+
+```python
+my_dictionary = {"name": "Brady"}
+```
+
+---
+
+#### Request looks like this
+
+<span class="centered">
+<img src="assets/Chrome Request.png" />
+</span>
+
+---
+
+#### Working With Multiple Arguments
+
+<span class="centered">
+<img src="assets/Query Param Example.png" />
+</span>
+
+```python
+
+from flask import Flask, request
+
+app = Flask(__name__)
+
+@app.route('/hello') 
+def hello():     
+	return "Here are all your args:" + str(request.args)
+
+app.run()
+```
+
+**Looks similar to**
+
+```python
+my_dictionary = {"name": "Brady", "age": 31, "city": "Salt Lake City"}
+```
+
+---
+
+#### Handling User Input with Query Parameters
+
+```python
+from flask import Flask, request  
+
+app = Flask(__name__)  
+
+@app.route('/greet') 
+def greet():     
+	name = request.args.get('name')  
+	if name:
+		return "Hello, " + {name}
+	else:
+		return 'Please enter your name.'
+
+app.run()
+```
+
+---
+
+#### Query parameters are Often Used to Filter, Sort or Search For Data
+
+```python
+
+from flask import Flask, request
+
+app = Flask(__name__)
+
+# A list of data in JSON format
+people = [
+    {"name": "Brady", "age": 31},
+    {"name": "Marcos", "age": 31},
+    {"name": "Nephi", "age": "??"},
+]
+
+# A route that filters the data by a 'name' query parameter
+@app.route('/people')
+def filter_people():
+    # Get the 'name' query parameter from the URL
+    name = request.args.get('name')
+
+    if name is None:
+        return str(people)
+
+    # Filter the data by name, if name is provided, using a loop
+    filtered_people = []
+    for person in people:
+        if person['name'] == name:
+            filtered_people.append(person)
+
+
+    return str(filtered_people)
+
+app.run(debug=True)
+
+# http://localhost:5000/people?name=John
+```