inital commit

notes_send.go

@@ -0,0 +1,73 @@
+package fa
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"strings"
+
+	"github.com/PuerkitoBio/goquery"
+
+	"git.anthrove.art/public/go-fa-api/internal/urls"
+)
+
+// SendNote sends a new private message (note) to a user. Requires login.
+//
+// FA's note form posts to /msg/send/ with a per-form CSRF key that must
+// be scraped from the notes inbox (or any page that renders the send
+// form). This method does the scrape + post in one call.
+//
+// Returns nil on success. ErrUnauthorized when not logged in.
+// *SystemMessageError when FA rejects the send (recipient blocked, rate
+// limited, etc.).
+func (c *Client) SendNote(ctx context.Context, to string, subject string, body string) error {
+	to = strings.TrimSpace(to)
+	if to == "" {
+		return fmt.Errorf("fa: SendNote: empty recipient")
+	}
+	if subject == "" {
+		return fmt.Errorf("fa: SendNote: empty subject")
+	}
+	if body == "" {
+		return fmt.Errorf("fa: SendNote: empty body")
+	}
+
+	// Scrape the form key from /msg/pms/. The notes inbox renders the same
+	// CSRF key in any note-related form on the page; we don't actually need
+	// to be replying to anything to harvest it.
+	var key string
+	err := c.fetch(ctx, urls.MsgPMs(), func(doc *goquery.Document) error {
+		key = findNoteKey(doc)
+		if key == "" {
+			return fmt.Errorf("%w: SendNote: could not locate form key on /msg/pms/", ErrUnauthorized)
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	v := url.Values{}
+	v.Set("key", key)
+	v.Set("to", to)
+	v.Set("subject", subject)
+	v.Set("message", body)
+	v.Set("send", "Send Note")
+	_, err = c.postForm(ctx, urls.Host+"/msg/send/", v)
+	return err
+}
+
+// findNoteKey looks for a hidden input named "key" inside any form that
+// targets the notes subsystem (/msg/send/ or /msg/pms/). FA reuses the
+// same key value across these forms within a session.
+func findNoteKey(doc *goquery.Document) string {
+	var key string
+	doc.Find("form[action='/msg/send/'] input[name='key'], form[action='/msg/pms/'] input[name='key'], form[action^='/msg/'] input[name='key']").EachWithBreak(func(_ int, sel *goquery.Selection) bool {
+		if v := strings.TrimSpace(trimAttr(sel, "value")); v != "" {
+			key = v
+			return false
+		}
+		return true
+	})
+	return key
+}