JAS Curl Runner – User Guide
This guide explains how to use the JAS Curl Runner VS Code extension to execute cURL requests directly from .jascurl files using CodeLens.
1. What Is JAS Curl Runner?
JAS Curl Runner allows you to:
- Write cURL requests in a structured file format
- Define and reuse variables across requests
- Group and scope variables for different environments
- Execute requests with a single click using CodeLens buttons in VS Code
No external tools like Postman are required.
2. Getting Started
2.1 Create a .jascurl File
Create a new file with the .jascurl extension in VS Code. All examples below use this file type.
3. Writing Your First Request
@id = 1
@baseUrl = https://jsonplaceholder.typicode.com
### Get User
curl -X GET {{baseUrl}}/users/{{id}}
How It Works
- Lines starting with
@ define variables
### marks a request block{{variable}} is replaced at runtime- A ▶ Execute Curl CodeLens button appears above each request
4. Executing Requests
- Hover over the request title (e.g.,
### Get User)
- Click the ▶ Execute Curl button
- Output appears in the VS Code terminal/output panel
5. Variables
5.1 Global Variables
@token = abc123
@baseUrl = https://api.example.com
Global variables are available to all requests in the file.
5.2 Using Variables in cURL
curl -X GET {{baseUrl}}/users \
-H "Authorization: Bearer {{token}}"
6. Group Variables
Groups allow you to define reusable variable sets for different environments or scenarios.
@fetch:group = {
id = 10
role = admin
}
7. Group Requests
Scopes allow a request to use variables from a specific group.
### Get Users
#group = @fetch
@id = 11
curl -X GET https://jsonplaceholder.typicode.com/users/{{id}}
Important: Request-level variables override group variables. Here, id = 11 overrides id = 10.
8. Variable Resolution Order
Variables are resolved in this priority:
- Request-level variables
- Group variables
- Global variables
The closest scope always wins.
9. Assertions (Optional)
Assertions help verify API responses.
@assert:status = 200
@assert:body.id exists
If an assertion fails, it will be reported in the output.
10. Running Multiple Requests
Each request block has its own ▶ Execute button. You can run requests individually or in sequence.
11. Best Practices
- Keep global variables at the top of the file
- Use groups for related APIs or environments
- Override values only when necessary
- Avoid hardcoding sensitive tokens
- Use descriptive request names (e.g.,
### Get User by ID)
12. Common Mistakes
| Mistake |
Reason |
| Using variables before defining them |
Variables must be declared first |
| Misspelling variable names |
Variable names are case-sensitive |
Forgetting ### before request name |
CodeLens will not appear |
| Using spaces in variable names |
Use underscore or camelCase instead |
13. Appearance & Customization
The JAS Curl Runner integrates seamlessly with VS Code's default theme. CodeLens buttons appear in a subtle gray color above request blocks for easy visibility without cluttering the editor.
14. Requirements
- Visual Studio Code v1.60 or later
- Node.js v16 or later
15. Known Limitations
- No streaming response support
- Minimal UI output
- No environment file support yet
16. Feedback & Support
If you encounter issues or have feature requests, please open an issue in the repository.
