API interaction scripts in Bash Scripting - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to send a GET request to example.com using curl.

Bash Scripting

curl [1] https://example.com

Drag options to blanks, or click blank then click option'

A-X GET

B-X POST

C-d

D-I

Attempts:

3 left

💡 Hint

Common Mistakes

Using -X POST instead of -X GET causes the server to expect data submission.

Using -d without data causes errors.

Using -I only fetches headers, not the full response.

The -X GET option tells curl to send a GET request, which is the default method to retrieve data.

2fill in blank

medium

Complete the code to include a JSON content type header in the curl request.

Bash Scripting

curl -X POST [1] -d '{"name":"John"}' https://example.com/api

Drag options to blanks, or click blank then click option'

A-H 'Content-Type: text/plain'

B-H 'Content-Type: application/json'

C-H 'Accept: text/html'

D-H 'Authorization: Bearer token'

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong Content-Type header causes the server to misinterpret the data.

Forgetting to add the header can cause the server to reject the request.

The header 'Content-Type: application/json' tells the server that the data sent is in JSON format.

3fill in blank

hard

Fix the error in the curl command to correctly send a POST request with JSON data.

Bash Scripting

curl -X POST -d [1] https://example.com/api

Drag options to blanks, or click blank then click option'

A'name=John'

B"name: John"

C"name=John"

D'{"name":"John"}'

Attempts:

3 left

💡 Hint

Common Mistakes

Using key=value format instead of JSON.

Using double quotes outside without escaping causes shell errors.

JSON data must be enclosed in single quotes with double quotes inside to be valid and correctly parsed.

4fill in blank

hard

Fill both blanks to save the response headers to a file and the body to another file.

Bash Scripting

curl -D [1] -o [2] https://example.com/api

Drag options to blanks, or click blank then click option'

Aheaders.txt

Bresponse.json

Coutput.log

Ddata.txt

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing -D and -o options.

Saving both headers and body to the same file.

The -D option saves headers to a file, and -o saves the response body to a file.

5fill in blank

hard

Fill all three blanks to create a curl command that sends a DELETE request with an authorization header and verbose output.

Bash Scripting

curl [1] [2] [3] https://example.com/api/item/123

Drag options to blanks, or click blank then click option'

A-X DELETE

B-H 'Authorization: Bearer abc123'

C-v

D-d '{}'

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to specify the DELETE method.

Not including the authorization header.

Missing verbose flag for debugging.

Use -X DELETE to specify the method, -H to add the auth header, and -v for verbose output.

Practice

1. What is the primary tool used in bash scripts to interact with web APIs?

easy

A. sed

B. grep

C. awk

D. curl

Solution

1. Step 1: Understand the purpose of each tool

   curl is used to send HTTP requests, while grep, awk, and sed are text processing tools.

2. Step 2: Identify the tool for API interaction

   Since APIs communicate over HTTP, curl is the correct tool to send requests and receive responses.

3. Final Answer:

   curl -> Option D

4. Quick Check:

   API calls use curl [OK]

Hint: Remember: curl sends web requests in bash [OK]

Common Mistakes:

• Confusing text tools like grep with API tools
• Using sed or awk for HTTP requests
• Thinking bash has a built-in HTTP client

2. Which of the following is the correct syntax to send a GET request to https://api.example.com/data using curl?

easy

A. curl https://api.example.com/data

B. curl --data https://api.example.com/data

C. curl -d https://api.example.com/data

D. curl -X POST https://api.example.com/data

Solution

1. Step 1: Understand default curl behavior

   By default, curl sends a GET request if no method is specified.

2. Step 2: Analyze options

   curl https://api.example.com/data sends a GET request simply by specifying the URL. The other options either specify POST or data, which changes the method.

3. Final Answer:

   curl https://api.example.com/data -> Option A

4. Quick Check:

   Default curl = GET request [OK]

Hint: No method means GET by default in curl [OK]

Common Mistakes:

• Using -X POST when GET is needed
• Adding -d or --data without POST method
• Confusing GET and POST syntax

3. What will be the output of this script snippet?

response=$(curl -s -H "Accept: application/json" https://api.example.com/status)
echo "$response"

medium

A. An error message about missing POST data

B. The raw JSON response from the API

C. Nothing, because the script has a syntax error

D. The HTTP status code only

Solution

1. Step 1: Understand the command

   The curl command uses -s for silent mode and sets the header to accept JSON. It fetches data from the API URL.

2. Step 2: Analyze the output

   The response variable stores the full API response body, which is expected to be JSON. The echo prints this JSON string.

3. Final Answer:

   The raw JSON response from the API -> Option B

4. Quick Check:

   Silent curl with JSON header returns JSON [OK]

Hint: Silent curl (-s) returns response body only [OK]

Common Mistakes:

• Expecting HTTP status code instead of body
• Thinking -H sets request method
• Assuming syntax error due to quotes

4. Identify the error in this script that sends JSON data to an API:

curl -X POST https://api.example.com/update -d '{"name":"John"}' -H 'Content-Type: application/json'

medium

A. The JSON data is not properly escaped

B. The -X POST option is missing

C. The Content-Type header should be text/plain

D. The URL is missing the protocol

Solution

1. Step 1: Check JSON data quoting

   The JSON string uses double quotes inside single quotes, but the inner double quotes are escaped with backslashes, which is unnecessary and can cause errors in bash.

2. Step 2: Correct quoting for JSON in bash

   Use single quotes around JSON without escaping double quotes, or use double quotes outside and escape inner quotes properly.

3. Final Answer:

   The JSON data is not properly escaped -> Option A

4. Quick Check:

   Proper JSON quoting avoids escape errors [OK]

Hint: Use single quotes around JSON to avoid escaping double quotes [OK]

Common Mistakes:

• Over-escaping quotes inside JSON
• Wrong Content-Type header
• Omitting -X POST when sending data

5. You want to write a bash script that sends a POST request with JSON data and saves the HTTP status code to a variable. Which command correctly does this?

hard

A. status=$(curl -X POST https://api.example.com/api -d '{"key":"value"}' -H 'Content-Type: application/json')

B. status=$(curl -X POST -H 'Content-Type: application/json' https://api.example.com/api -d '{"key":"value"}')

C. status=$(curl -X POST -d '{"key":"value"}' -H 'Content-Type: application/json' https://api.example.com/api -w "%{http_code}" -o /dev/null -s)

D. status=$(curl -X POST -d '{"key":"value"}' https://api.example.com/api -H 'Content-Type: application/json' -i)

Solution

1. Step 1: Understand how to capture HTTP status code

   The -w "%{http_code}" option tells curl to output the HTTP status code after the response. The -o /dev/null discards the response body, and -s silences progress.

2. Step 2: Check command correctness

   status=$(curl -X POST -d '{"key":"value"}' -H 'Content-Type: application/json' https://api.example.com/api -w "%{http_code}" -o /dev/null -s) correctly uses all these options and assigns the status code to the variable. Other options either capture the response body or include headers, not just the status code.

3. Final Answer:

   status=$(curl -X POST -d '{"key":"value"}' -H 'Content-Type: application/json' https://api.example.com/api -w "%{http_code}" -o /dev/null -s) -> Option C

4. Quick Check:

   Use -w with -o /dev/null to get status code [OK]

Hint: Use curl -w with -o /dev/null to get only status code [OK]

Common Mistakes:

• Capturing full response instead of status code
• Missing -w option for status code
• Not silencing output with -s