Support exporting email subscribers list

This adds a new /api/collections/{alias} endpoint that downloads all
collection subscribers as a CSV file.

Ref T828

email.go

@@ -11,6 +11,7 @@
 package writefreely
 
 import (
+	"bytes"
 	"database/sql"
 	"encoding/json"
 	"fmt"
@@ -180,6 +181,40 @@ func handleCreateEmailSubscription(app *App, w http.ResponseWriter, r *http.Requ
 	return impart.WriteSuccess(w, "", http.StatusAccepted)
 }
 
+func handleExportEmailSubscriptions(app *App, w http.ResponseWriter, r *http.Request) ([]byte, string, error) {
+	vars := mux.Vars(r)
+	var err error
+	alias := vars["alias"]
+	filename := ""
+	u := getUserSession(app, r)
+	if u == nil {
+		return nil, filename, ErrNotLoggedIn
+	}
+	c, err := app.db.GetCollection(alias)
+	if err != nil {
+		return nil, filename, err
+	}
+
+	// Verify permissions / ownership
+	if u.ID != c.OwnerID {
+		return nil, filename, ErrForbiddenCollectionAccess
+	}
+
+	filename = "subscribers-" + alias + "-" + time.Now().Truncate(time.Second).UTC().Format("200601021504")
+
+	subs, err := app.db.GetEmailSubscribers(c.ID, true)
+	if err != nil {
+		return nil, filename, err
+	}
+
+	var data []byte
+	for _, sub := range subs {
+		data = append(data, []byte(sub.Email.String+"\n")...)
+	}
+	data = bytes.TrimRight(data, "\n")
+	return data, filename, err
+}
+
 func handleDeleteEmailSubscription(app *App, w http.ResponseWriter, r *http.Request) error {
 	alias := collectionAliasFromReq(r)
 

errors.go

@@ -26,6 +26,7 @@ var (
 	ErrNotLoggedIn    = impart.HTTPError{http.StatusUnauthorized, "Not logged in."}
 
 	ErrForbiddenCollection        = impart.HTTPError{http.StatusForbidden, "You don't have permission to add to this collection."}
+	ErrForbiddenCollectionAccess  = impart.HTTPError{http.StatusForbidden, "You don't have permission to access this collection."}
 	ErrForbiddenEditPost          = impart.HTTPError{http.StatusForbidden, "You don't have permission to update this post."}
 	ErrUnauthorizedEditPost       = impart.HTTPError{http.StatusUnauthorized, "Invalid editing credentials."}
 	ErrUnauthorizedGeneral        = impart.HTTPError{http.StatusUnauthorized, "You don't have permission to do that."}

routes.go

@@ -148,6 +148,7 @@ func InitRoutes(apper Apper, r *mux.Router) *mux.Router {
 	apiColls.HandleFunc("/{alias}/collect", handler.All(addPost)).Methods("POST")
 	apiColls.HandleFunc("/{alias}/pin", handler.All(pinPost)).Methods("POST")
 	apiColls.HandleFunc("/{alias}/unpin", handler.All(pinPost)).Methods("POST")
+	apiColls.HandleFunc("/{alias}/email/subscribers/export.csv", handler.Download(handleExportEmailSubscriptions, UserLevelUser)).Methods("GET")
 	apiColls.HandleFunc("/{alias}/email/subscribe", handler.All(handleCreateEmailSubscription)).Methods("POST")
 	apiColls.HandleFunc("/{alias}/email/subscribe", handler.All(handleDeleteEmailSubscription)).Methods("DELETE")
 	apiColls.HandleFunc("/{collection}/email/unsubscribe", handler.All(handleDeleteEmailSubscription)).Methods("GET")

templates/user/subscribers.tmpl

@@ -63,7 +63,11 @@
 					<p><strong>Email subscriptions are disabled on this server</strong>, so no new emails will be sent out.</p>
 				</div>
 			{{end}}
-			{{if not .EmailSubsEnabled}}
+			{{if .EmailSubsEnabled}}
+				<div class="row toolbar ends">
+					<a href="/api/collections/{{.Collection.Alias}}/email/subscribers/export.csv">Export list</a>
+				</div>
+			{{else}}
 				<div class="alert info">
 					<p><strong>Email subscriptions are disabled</strong>. {{if .EmailSubs}}No new emails will be sent out.{{end}} To enable email subscriptions, turn the option on from your blog's <a href="/me/c/{{.Collection.Alias}}#updates">Customize</a> page.</p>
 				</div>