GET /yaml

GET /yaml alias: /yaml

Returns a well-formed YAML 1.2 document: scalars, mapping, sequence, and a sane anchor + merge-key. No Norway-problem scalars, no cycles, no duplicate keys, no tag lies. Served as application/yaml. Counterpart to /yaml.

expect: 200 OK with Content-Type: application/yaml. Spec-compliant YAML 1.2 that parses identically under YAML 1.1 and 1.2 parsers. Build YAML config loaders against this, then flip hostname to chaos.catastrophic.io to test adversity.

bash

curl -si 'https://not.catastrophic.io/yaml'

# pip install pyyaml ruamel.yaml
import urllib.request, yaml
resp = urllib.request.urlopen("https://not.catastrophic.io/yaml")
print("Content-Type:", resp.headers.get("Content-Type"))
print("X-Chaos-Yaml-Mode:", resp.headers.get("X-Chaos-Yaml-Mode"))
print("X-Chaos-Yaml-Note:", resp.headers.get("X-Chaos-Yaml-Note"))
text = resp.read().decode()
try:
    # safe_load uses YAML 1.1 in older PyYAML; the Norway problem surfaces here.
    parsed = yaml.safe_load(text)
    print("parsed:", parsed)
except yaml.YAMLError as e:
    print("parser rejected:", e)

// npm: js-yaml (YAML 1.2)
import yaml from "js-yaml";
const res = await fetch("https://not.catastrophic.io/yaml");
console.log("Content-Type:", res.headers.get("content-type"));
console.log("X-Chaos-Yaml-Mode:", res.headers.get("x-chaos-yaml-mode"));
console.log("X-Chaos-Yaml-Note:", res.headers.get("x-chaos-yaml-note"));
const text = await res.text();
try {
  console.log("parsed:", yaml.load(text));
} catch (e) {
  console.log("parser rejected:", e.message);
}

package main

// go get gopkg.in/yaml.v2  (YAML 1.1 — sees Norway problem)
// go get gopkg.in/yaml.v3  (YAML 1.2)
import (
    "fmt"
    "io"
    "net/http"

    "gopkg.in/yaml.v3"
)

func main() {
    resp, _ := http.Get("https://not.catastrophic.io/yaml")
    defer resp.Body.Close()
    raw, _ := io.ReadAll(resp.Body)
    fmt.Println("Content-Type:", resp.Header.Get("Content-Type"))
    fmt.Println("X-Chaos-Yaml-Mode:", resp.Header.Get("X-Chaos-Yaml-Mode"))
    var out map[string]any
    if err := yaml.Unmarshal(raw, &out); err != nil {
        fmt.Println("unmarshal rejected:", err)
    } else {
        fmt.Println("decoded keys:", out)
    }
}

// Cargo.toml: reqwest = { version = "0.12", features = ["blocking"] }
//            serde_yaml = "0.9"  (YAML 1.2)
fn main() -> Result<(), Box> {
    let resp = reqwest::blocking::get("https://not.catastrophic.io/yaml")?;
    println!("Content-Type: {:?}", resp.headers().get("content-type"));
    println!("X-Chaos-Yaml-Mode: {:?}", resp.headers().get("x-chaos-yaml-mode"));
    let text = resp.text()?;
    match serde_yaml::from_str::(&text) {
        Ok(v) => println!("parsed: {:?}", v),
        Err(e) => println!("parser rejected: {}", e),
    }
    Ok(())
}

// SnakeYAML on the classpath (YAML 1.1 by default).
import java.net.URI;
import java.net.http.*;
import org.yaml.snakeyaml.Yaml;

public class YamlChaos {
    public static void main(String[] args) throws Exception {
        var client = HttpClient.newHttpClient();
        var req = HttpRequest.newBuilder(URI.create("https://not.catastrophic.io/yaml")).build();
        var resp = client.send(req, HttpResponse.BodyHandlers.ofString());
        System.out.println("Content-Type: " +
            resp.headers().firstValue("Content-Type").orElse(""));
        System.out.println("X-Chaos-Yaml-Mode: " +
            resp.headers().firstValue("X-Chaos-Yaml-Mode").orElse(""));
        try {
            Object parsed = new Yaml().load(resp.body());
            System.out.println("parsed: " + parsed);
        } catch (Exception e) {
            System.out.println("parser rejected: " + e.getMessage());
        }
    }
}

// NuGet: YamlDotNet (YAML 1.2)
using YamlDotNet.Serialization;
using var client = new HttpClient();
var resp = await client.GetAsync("https://not.catastrophic.io/yaml");
Console.WriteLine($"Content-Type: {resp.Content.Headers.ContentType}");
Console.WriteLine($"X-Chaos-Yaml-Mode: " +
    $"{resp.Headers.GetValues("X-Chaos-Yaml-Mode").FirstOrDefault()}");
var text = await resp.Content.ReadAsStringAsync();
try {
    var parsed = new Deserializer().Deserialize