URLs and their structure in Intro to Computing - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does URL stand for?

URL stands for Uniform Resource Locator. It is the address used to find resources on the internet, like websites or files.

beginner

Name the main parts of a URL.

A URL has these main parts:
1. Protocol (like http or https)
2. Domain name (like www.example.com)
3. Optional port number (like :80)
4. Path (like /page1)
5. Optional query parameters (like ?id=123)
6. Optional fragment (like #section2)

beginner

What is the role of the protocol in a URL?

The protocol tells the browser how to communicate with the server. For example, 'http' or 'https' means to use the HyperText Transfer Protocol, where 'https' is secure.

beginner

Explain the difference between domain and path in a URL.

The domain is like the street address of a building (e.g., www.example.com). The path is like the room number inside the building (e.g., /about). Together, they tell the browser exactly where to go.

intermediate

What are query parameters in a URL?

Query parameters come after a question mark (?) in a URL. They send extra information to the server, like search terms or filters. For example, '?search=books' tells the server to look for books.

Which part of the URL specifies the website's address?

A Protocol

B Path

C Domain name

D Query parameters

The domain name is the main address of the website, like www.example.com.

What symbol starts the query parameters in a URL?

A ?

B /

C #

D :

Query parameters always start with a question mark (?) in a URL.

In the URL 'https://www.site.com:8080/page?item=5#top', what does ':8080' represent?

A Path

B Protocol

C Fragment

D Port number

The ':8080' is the port number telling the browser which port to use to connect.

What does the fragment part of a URL do?

A Points to a section within the page

B Sends data to the server

C Specifies the server location

D Defines the protocol

The fragment, after a #, points to a specific section inside the webpage.

Which protocol indicates a secure connection?

A http

B https

C smtp

D ftp

'https' means the connection is secure using encryption.

Describe the structure of a URL and explain the purpose of each part.

Think of a URL like a mailing address with extra details.

Explain how query parameters and fragments are used in URLs with examples.

Consider how you search or jump to parts of a webpage.

Practice

1. Which part of a URL specifies the protocol used to access a resource?
https://www.example.com:8080/path?query=123#section

easy

A. www.example.com

B. 8080

C. https

D. /path

Solution

1. Step 1: Identify the scheme in the URL

   The scheme is the part before the first colon (:), which defines the protocol.

2. Step 2: Locate the scheme in the example URL

   In https://www.example.com:8080/path?query=123#section, the scheme is https.

3. Final Answer:

   https -> Option C

4. Quick Check:

   Scheme = https [OK]

Hint: Look before :// for the protocol name [OK]

Common Mistakes:

• Confusing domain with scheme
• Thinking port number is the protocol
• Selecting path as scheme

2. Which of the following is the correct syntax for a URL including a port number?

easy

A. http://example.com:80

B. http://:80example.com

C. http://example.com/80

D. http://example.com?80

Solution

1. Step 1: Understand port placement in URL syntax

   The port number comes after the domain, separated by a colon (:).

2. Step 2: Check each option for correct port syntax

   http://example.com:80 uses http://example.com:80, which correctly places port 80 after the domain with a colon.

3. Final Answer:

   http://example.com:80 -> Option A

4. Quick Check:

   Port follows domain with colon [OK]

Hint: Port number always follows domain with a colon [OK]

Common Mistakes:

• Placing port before domain
• Using slash instead of colon for port
• Adding port as query parameter

3. What is the full path and query part of this URL?
https://shop.example.com/products/item?id=12345&color=red#reviews

medium

A. /products/item?id=12345&color=red

B. /products/item#reviews

C. ?id=12345&color=red#reviews

D. /products/item?id=12345&color=red#reviews

Solution

1. Step 1: Identify path and query parts in the URL

   The path is the part after the domain up to the question mark (?), and the query is after the question mark up to the hash (#).

2. Step 2: Extract path and query from the example URL

   Path: /products/item, Query: ?id=12345&color=red. The fragment #reviews is not part of path or query.

3. Final Answer:

   /products/item?id=12345&color=red -> Option A

4. Quick Check:

   Path + Query = /products/item?id=12345&color=red [OK]

Hint: Path starts with /, query starts with ? [OK]

Common Mistakes:

• Including fragment (#reviews) in path or query
• Confusing query with fragment
• Ignoring query parameters

4. Identify the error in this URL:
ftp//files.example.com/downloads/file.zip

medium

A. Path should start with a question mark

B. Missing colon after scheme

C. Domain name is invalid

D. Port number is missing

Solution

1. Step 1: Check the scheme syntax

   The scheme must end with a colon (:), e.g., ftp:.

2. Step 2: Locate the error in the URL

   The URL has ftp// missing the colon after ftp. Correct form is ftp://.

3. Final Answer:

   Missing colon after scheme -> Option B

4. Quick Check:

   Scheme ends with : [OK]

Hint: Scheme must end with : before // [OK]

Common Mistakes:

• Ignoring missing colon in scheme
• Thinking domain is invalid
• Expecting port number always

5. You want to create a URL to access a user profile page with user ID 789 and show the 'settings' section. Which URL correctly uses path, query, and fragment?
Base URL: https://app.example.com

hard

A. https://app.example.com/user?id=789#settings?section=profile

B. https://app.example.com/user/789#settings?section=profile

C. https://app.example.com/user/789?section=settings#profile

D. https://app.example.com/user/789?section=settings#settings

Solution

1. Step 1: Understand URL parts for user profile

   The user ID should be part of the path (/user/789), the section to show is a query parameter (?section=settings), and the fragment points to a page section (#settings).

2. Step 2: Evaluate each option for correct structure

   https://app.example.com/user/789?section=settings#settings correctly places user ID in path, section in query, and fragment as #settings. Others mix fragment and query incorrectly or mismatch sections.

3. Final Answer:

   https://app.example.com/user/789?section=settings#settings -> Option D

4. Quick Check:

   Path + Query + Fragment correct [OK]

Hint: Path for ID, query for filters, fragment for page section [OK]

Common Mistakes:

• Swapping query and fragment parts
• Putting ID in query instead of path
• Using fragment with query parameters