add user invite instructions

this adds a new page with instructions for sharing user invites

if a user clicks the link for one of their own invite codes they are
directed to a page with clear instructions for it's use.

if a user clicks another users link they are redirectec to their account
settings witha flash telling them they do not need to register.

database.go

@@ -2257,6 +2257,19 @@ func (db *datastore) GetUserInvite(id string) (*Invite, error) {
 	return &i, nil
 }
 
+// IsUsersInvite returns true if the user with ID created the invite with code
+// and an error other than sql no rows, if any. Will return false in the event
+// of an error.
+func (db *datastore) IsUsersInvite(code string, userID int64) (bool, error) {
+	var id string
+	err := db.QueryRow("SELECT id FROM userinvites WHERE id = ? AND owner_id = ?", code, userID).Scan(&id)
+	if err != nil && err != sql.ErrNoRows {
+		log.Error("Failed selecting invite: %v", err)
+		return false, err
+	}
+	return id != "", nil
+}
+
 func (db *datastore) GetUsersInvitedCount(id string) int64 {
 	var count int64
 	err := db.QueryRow("SELECT COUNT(*) FROM usersinvited WHERE invite_id = ?", id).Scan(&count)

invites.go

@@ -12,15 +12,16 @@ package writefreely
 
 import (
 	"database/sql"
+	"html/template"
+	"net/http"
+	"strconv"
+	"time"
+
 	"github.com/gorilla/mux"
 	"github.com/writeas/impart"
 	"github.com/writeas/nerds/store"
 	"github.com/writeas/web-core/log"
 	"github.com/writeas/writefreely/page"
-	"html/template"
-	"net/http"
-	"strconv"
-	"time"
 )
 
 type Invite struct {
@@ -109,6 +110,26 @@ func handleCreateUserInvite(app *App, u *User, w http.ResponseWriter, r *http.Re
 func handleViewInvite(app *App, w http.ResponseWriter, r *http.Request) error {
 	inviteCode := mux.Vars(r)["code"]
 
+	if u := getUserSession(app, r); u != nil {
+		// check if invite belongs to another user
+		// error can be ignored as not important in this case
+		if ownInvite, _ := app.db.IsUsersInvite(inviteCode, u.ID); !ownInvite {
+			addSessionFlash(app, w, r, "No need for an invite, You are already registered.", nil)
+			// show homepage
+			return impart.HTTPError{http.StatusFound, "/me/settings"}
+		}
+		// show invite instructions
+		p := struct {
+			*UserPage
+			InviteID string
+		}{
+			UserPage: NewUserPage(app, r, u, "Invite Instructions", nil),
+			InviteID: inviteCode,
+		}
+		showUserPage(w, "invite-instructions", p)
+		return nil
+	}
+
 	i, err := app.db.GetUserInvite(inviteCode)
 	if err != nil {
 		return err

routes.go

@@ -11,13 +11,14 @@
 package writefreely
 
 import (
+	"net/http"
+	"path/filepath"
+	"strings"
+
 	"github.com/gorilla/mux"
 	"github.com/writeas/go-webfinger"
 	"github.com/writeas/web-core/log"
 	"github.com/writefreely/go-nodeinfo"
-	"net/http"
-	"path/filepath"
-	"strings"
 )
 
 // InitStaticRoutes adds routes for serving static files.
@@ -151,7 +152,7 @@ func InitRoutes(apper Apper, r *mux.Router) *mux.Router {
 	// Handle special pages first
 	write.HandleFunc("/login", handler.Web(viewLogin, UserLevelNoneRequired))
 	write.HandleFunc("/signup", handler.Web(handleViewLanding, UserLevelNoneRequired))
-	write.HandleFunc("/invite/{code}", handler.Web(handleViewInvite, UserLevelNoneRequired)).Methods("GET")
+	write.HandleFunc("/invite/{code}", handler.Web(handleViewInvite, UserLevelOptional)).Methods("GET")
 	// TODO: show a reader-specific 404 page if the function is disabled
 	write.HandleFunc("/read", handler.Web(viewLocalTimeline, UserLevelReader))
 	RouteRead(handler, UserLevelReader, write.PathPrefix("/read").Subrouter())

templates/user/invite-instructions.tmpl

@@ -0,0 +1,25 @@
+{{define "invite-instructions"}}
+{{template "header" .}}
+<style>
+  .copy-link {
+    width: 100%;
+    margin: 2em 0;
+    text-align: center;
+    font-size-adjust: .7;
+    color: #555;
+  }
+</style>
+<div class="snug content-container">
+	<h1>Invite Instructions</h1>
+  <p>This is a special link that you can send to anyone you want to join <em>{{ .SiteName }}</em>. Copy the link below and paste it into an email, instant message, or text message and send it to the person you want. When they navigate to the link, they'll be able to create an account.</p>
+  <input
+  class="copy-link"
+  type="text"
+  name="invite-url"
+  value="{{$.Host}}/invite/{{.InviteID}}"
+  onfocus="if (this.select) this.select(); else this.setSelectionRange(0, this.value.length);"
+  readonly/>
+</div>
+
+{{template "footer" .}}
+{{end}}