feat(protocols): add ForcAD HTTP protocol support

cookiefarm/pkg/protocols/forcad_http.go

@@ -0,0 +1,133 @@
+//go:build ignore
+
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"models"
+	"net/http"
+	"strings"
+
+	"protocols"
+)
+
+// Submit forwards flags to a ForcAD gameserver HTTP receiver (https://github.com/pomo-mondreganto/ForcAD.git)
+//
+// ForcAD exposes `PUT /flags` (see backend/services/http_receiver/views.py),
+// authenticated via the `X-Team-Token` header, with a JSON list of flag
+// strings as body (max 100 per request).
+//
+// On success the receiver answers with a JSON array of objects shaped like:
+//
+//	[{"msg": "[<flag>] <message>", "flag": "<flag>"}]
+//
+// Note there is NO explicit status field: the verdict has to be derived from
+// the human-readable message. On request-level failures (bad token, game not
+// started, body too large, rate limit, ...) the server answers with a JSON
+// object `{"error": "..."}` or an HTML error page instead, with a non-2xx
+// status code. In those cases we return an error so the whole batch stays
+// unsubmitted (status = 0) and is retried on the next tick
+func Submit(url string, teamToken string, flags []string) ([]protocols.ResponseProtocol, error) {
+	jsonData, err := json.Marshal(flags)
+	if err != nil {
+		return nil, fmt.Errorf("error during marshalling: %w", err)
+	}
+
+	req, err := http.NewRequest(http.MethodPut, url, bytes.NewBuffer(jsonData))
+	if err != nil {
+		return nil, fmt.Errorf("error during request creation: %w", err)
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("X-Team-Token", teamToken)
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("error during request submission: %w", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("error during response reading: %w", err)
+	}
+
+	// Anything other than 2xx is a request-level failure (invalid token,
+	// game not started, 413 body too large, 429 rate limit, nginx HTML page,
+	// ...). Surface it as an error so the batch is retried instead of trying
+	// to parse a non-array body
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return nil, fmt.Errorf("checker returned status %d: %s", resp.StatusCode, errorMessage(body))
+	}
+
+	var responses []struct {
+		Flag string `json:"flag"`
+		Msg  string `json:"msg"`
+	}
+	if err := json.Unmarshal(body, &responses); err != nil {
+		// 200 but not the expected array: most likely a top-level
+		// `{"error": "..."}` object. Report it so the batch is retried
+		return nil, fmt.Errorf("error during response parsing: %w (body: %s)", err, errorMessage(body))
+	}
+
+	responsesParsed := make([]protocols.ResponseProtocol, len(responses))
+	for i := range responses {
+		responsesParsed[i].Flag = responses[i].Flag
+		responsesParsed[i].Msg = cleanMessage(responses[i].Msg, responses[i].Flag)
+		responsesParsed[i].Status = statusFromMessage(responses[i].Msg)
+	}
+
+	return responsesParsed, nil
+}
+
+// errorMessage extracts a human-readable message from a non-array response
+// body, falling back to a trimmed raw snippet (e.g. an nginx HTML page)
+func errorMessage(body []byte) string {
+	var e struct {
+		Error string `json:"error"`
+	}
+	if err := json.Unmarshal(body, &e); err == nil && e.Error != "" {
+		return e.Error
+	}
+
+	snippet := strings.TrimSpace(string(body))
+	if len(snippet) > 200 {
+		snippet = snippet[:200] + "..."
+	}
+	return snippet
+}
+
+// cleanMessage strips the leading "[<flag>] " prefix that ForcAD prepends to
+// every message, without assuming it is always present.
+func cleanMessage(msg, flag string) string {
+	msg = strings.TrimSpace(msg)
+	if prefix := "[" + flag + "]"; strings.HasPrefix(msg, prefix) {
+		return strings.TrimSpace(strings.TrimPrefix(msg, prefix))
+	}
+	return msg
+}
+
+func statusFromMessage(msg string) int64 {
+	m := strings.ToLower(msg)
+
+	switch {
+	case strings.Contains(m, "accepted"):
+		return models.StatusAccepted
+	case strings.Contains(m, "already stolen"),
+		strings.Contains(m, "your own"),
+		strings.Contains(m, "invalid"),
+		strings.Contains(m, "too old"):
+		return models.StatusDenied
+	case strings.Contains(m, "service is down"),
+		strings.Contains(m, "not available"):
+		return models.StatusNotValid
+	default:
+		// Unknown verdict: mark as Error (terminal) to avoid an infinite
+		// resubmission loop, but it will show up in the logs.
+		return models.StatusError
+	}
+}