Documentation
Examples
HTTP Fetch

HTTP Fetch

Making HTTP requests and displaying JSON data.

HTTP Fetch Example

Code 

require(["v0.4", "@gui", "@http"])

let urlEntry = widget.NewEntry()
urlEntry.SetPlaceHolder("https://api.github.com/users/octocat")
urlEntry.Text = "https://api.github.com/users/octocat"

let resultText = widget.NewLabel("")
resultText.Wrapping = constants.TextWrapWord

let statusLabel = widget.NewLabel("Ready")

let fetchButton = widget.NewButton("Fetch", () => {
    let url = urlEntry.Text
    
    if (url == "") {
        statusLabel.Text = "Error: URL is required"
        return
    }
    
    statusLabel.Text = "Fetching..."
    
    go(() => {
        // Make HTTP request in background
        let response = http.get(url)
        
        // Update UI on main thread
        window.Do(() => {
            if (response.status == 200) {
                let data = response.json()
                let formatted = sprintf(
                    "Name: %s\nBio: %s\nFollowers: %d\nPublic Repos: %d",
                    data["name"],
                    data["bio"],
                    data["followers"],
                    data["public_repos"]
                )
                resultText.Text = formatted
                statusLabel.Text = "Success!"
            } else {
                resultText.Text = ""
                statusLabel.Text = sprintf("Error: HTTP %d", response.status)
            }
        })
    })
})

let content = container.NewBorder(
    container.NewVBox([
        widget.NewLabel("GitHub User API Demo"),
        urlEntry,
        fetchButton,
        statusLabel,
    ]),
    nil,
    nil,
    nil,
    container.NewScroll(resultText)
)

window.SetContent(content)

Explanation

  1. HTTP Module - Enable with require(["@http"])
  2. Background Request - Use go() for non-blocking HTTP calls
  3. JSON Parsing - response.json() parses JSON response
  4. Thread Safety - Use window.Do() to update GUI from background
  5. Status Handling - Check response.status for errors

Key Concepts

  • Concurrency: go() runs function in background goroutine
  • Thread Safety: Never update GUI directly from background—use window.Do()
  • JSON APIs: Parse JSON responses with .json() method
  • Error Handling: Check HTTP status codes before processing

Try It 

fynerisor http-fetch.risor

Test with different APIs:

  • https://api.github.com/users/octocat
  • https://jsonplaceholder.typicode.com/posts/1
  • https://api.github.com/repos/fyne-io/fyne
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