persist app title + code refactoring

* Update EN, IT langs

Fixed EN lang mistype error
Added missing IT keys + added more translations

* Fixed files location

- livestreams.dat now uses same location as session.data (if specified on config.yml)
- .db.lock now uses same location as database file (if specified on config.yml)

* Update migrate.go

revert edit

---------

Co-authored-by: Marco Piovanello <35533749+marcopiovanello@users.noreply.github.com>

.gitignore

@@ -29,3 +29,4 @@ frontend/.yarn/install-state.gz
 livestreams.dat
 .vite/deps
 archive.txt
+web_config.yml

frontend/package.json

@@ -18,11 +18,12 @@
     "@mui/icons-material": "^6.2.0",
     "@mui/material": "^6.2.0",
     "fp-ts": "^2.16.5",
+    "jotai": "^2.10.3",
+    "jotai-cache": "^0.5.0",
     "react": "^19.0.0",
     "react-dom": "^19.0.0",
     "react-router-dom": "^6.23.1",
     "react-virtuoso": "^4.7.11",
-    "jotai": "^2.10.3",
     "rxjs": "^7.8.1"
   },
   "devDependencies": {

frontend/pnpm-lock.yaml

@@ -32,6 +32,9 @@ importers:
       jotai:
         specifier: ^2.10.3
         version: 2.10.3(@types/react@19.0.1)(react@19.0.0)
+      jotai-cache:
+        specifier: ^0.5.0
+        version: 0.5.0(jotai@2.10.3(@types/react@19.0.1)(react@19.0.0))
       react:
         specifier: ^19.0.0
         version: 19.0.0
@@ -737,6 +740,11 @@ packages:
   is-core-module@2.12.1:
     resolution: {integrity: sha512-Q4ZuBAe2FUsKtyQJoQHlvP8OvBERxO3jEmy1I7hcRXcJBGGHFh/aJBswbXuS9sgrDH2QUO8ilkwNPHvHMd8clg==}
 
+  jotai-cache@0.5.0:
+    resolution: {integrity: sha512-29pUuEfSXL7Ba6lxZmiNDARc73TspWzAzCy0jCkk2uEOnFJ6kaUBZTp/AZSwnIsh1ndfUfM9/QpbLU7uJAQL0A==}
+    peerDependencies:
+      jotai: '>=2.0.0'
+
   jotai@2.10.3:
     resolution: {integrity: sha512-Nnf4IwrLhNfuz2JOQLI0V/AgwcpxvVy8Ec8PidIIDeRi4KCFpwTFIpHAAcU+yCgnw/oASYElq9UY0YdUUegsSA==}
     engines: {node: '>=12.20.0'}
@@ -1512,6 +1520,10 @@ snapshots:
     dependencies:
       has: 1.0.3
 
+  jotai-cache@0.5.0(jotai@2.10.3(@types/react@19.0.1)(react@19.0.0)):
+    dependencies:
+      jotai: 2.10.3(@types/react@19.0.1)(react@19.0.0)
+
   jotai@2.10.3(@types/react@19.0.1)(react@19.0.0):
     optionalDependencies:
       '@types/react': 19.0.1

frontend/src/Layout.tsx

@@ -16,13 +16,13 @@ import ListItemButton from '@mui/material/ListItemButton'
 import ListItemIcon from '@mui/material/ListItemIcon'
 import ListItemText from '@mui/material/ListItemText'
 import Toolbar from '@mui/material/Toolbar'
-import Typography from '@mui/material/Typography'
 import { grey } from '@mui/material/colors'
 import { useAtomValue } from 'jotai'
 import { useMemo, useState } from 'react'
 import { Link, Outlet } from 'react-router-dom'
 import { settingsState } from './atoms/settings'
 import AppBar from './components/AppBar'
+import { AppTitle } from './components/AppTitle'
 import Drawer from './components/Drawer'
 import Footer from './components/Footer'
 import Logout from './components/Logout'
@@ -76,15 +76,7 @@ export default function Layout() {
             >
               <Menu />
             </IconButton>
-            <Typography
+            <AppTitle />
-              component="h1"
-              variant="h6"
-              color="inherit"
-              noWrap
-              sx={{ flexGrow: 1 }}
-            >
-              {settings.appTitle}
-            </Typography>
           </Toolbar>
         </AppBar>
         <Drawer variant="permanent" open={open}>

frontend/src/atoms/downloadTemplate.ts

@@ -1,12 +1,12 @@
 import { getOrElse } from 'fp-ts/lib/Either'
 import { pipe } from 'fp-ts/lib/function'
-import { atom } from 'jotai'
+import { atomWithCache } from 'jotai-cache'
 import { atomWithStorage } from 'jotai/utils'
 import { ffetch } from '../lib/httpClient'
 import { CustomTemplate } from '../types'
 import { serverSideCookiesState, serverURL } from './settings'
 
-export const cookiesTemplateState = atom<Promise<string>>(async (get) =>
+export const cookiesTemplateState = atomWithCache<Promise<string>>(async (get) =>
   await get(serverSideCookiesState)
     ? '--cookies=cookies.txt'
     : ''
@@ -22,7 +22,7 @@ export const filenameTemplateState = atomWithStorage(
   localStorage.getItem('lastFilenameTemplate') ?? ''
 )
 
-export const savedTemplatesState = atom<Promise<CustomTemplate[]>>(async (get) => {
+export const savedTemplatesState = atomWithCache<Promise<CustomTemplate[]>>(async (get) => {
   const task = ffetch<CustomTemplate[]>(`${get(serverURL)}/api/v1/template/all`)
   const either = await task()
 
@@ -30,5 +30,4 @@ export const savedTemplatesState = atom<Promise<CustomTemplate[]>>(async (get) =
     either,
     getOrElse(() => new Array<CustomTemplate>())
   )
-}
+})
-)

frontend/src/atoms/settings.ts

@@ -1,9 +1,9 @@
 import { pipe } from 'fp-ts/lib/function'
 import { matchW } from 'fp-ts/lib/TaskEither'
+import { atom } from 'jotai'
+import { atomWithStorage } from 'jotai/utils'
 import { ffetch } from '../lib/httpClient'
 import { prefersDarkMode } from '../utils'
-import { atomWithStorage } from 'jotai/utils'
-import { atom } from 'jotai'
 
 export const languages = [
   'catalan',
@@ -121,11 +121,15 @@ export const appTitleState = atomWithStorage(
 export const serverAddressAndPortState = atom((get) => {
   if (get(servedFromReverseProxySubDirState)) {
     return `${get(serverAddressState)}/${get(servedFromReverseProxySubDirState)}/`
+      .replaceAll('"', '')    // XXX: atomWithStorage uses JSON.stringify to serialize
+      .replaceAll('//', '/')  //      which puts extra double quotes.
   }
   if (get(servedFromReverseProxyState)) {
     return `${get(serverAddressState)}`
+      .replaceAll('"', '')
   }
   return `${get(serverAddressState)}:${get(serverPortState)}`
+    .replaceAll('"', '')
 })
 
 export const serverURL = atom((get) =>
@@ -135,14 +139,12 @@ export const serverURL = atom((get) =>
 export const rpcWebSocketEndpoint = atom((get) => {
   const proto = window.location.protocol === 'https:' ? 'wss:' : 'ws:'
   return `${proto}//${get(serverAddressAndPortState)}/rpc/ws`
-}
+})
-)
 
 export const rpcHTTPEndpoint = atom((get) => {
   const proto = window.location.protocol
   return `${proto}//${get(serverAddressAndPortState)}/rpc/http`
-}
+})
-)
 
 export const serverSideCookiesState = atom<Promise<string>>(async (get) => await pipe(
   ffetch<Readonly<{ cookies: string }>>(`${get(serverURL)}/api/v1/cookies`),
@@ -180,5 +182,4 @@ export const settingsState = atom<SettingsState>((get) => ({
   listView: get(listViewState),
   servedFromReverseProxy: get(servedFromReverseProxyState),
   appTitle: get(appTitleState)
-})
+}))
-)

frontend/src/components/AppTitle.tsx

@@ -0,0 +1,33 @@
+import { Typography } from '@mui/material'
+import { useAtom } from 'jotai'
+import { useEffect } from 'react'
+import { appTitleState } from '../atoms/settings'
+import useFetch from '../hooks/useFetch'
+
+export const AppTitle: React.FC = () => {
+  const [appTitle, setAppTitle] = useAtom(appTitleState)
+
+  const { data } = useFetch<{ title: string }>('/webconfig')
+
+  useEffect(() => {
+    if (data?.title) {
+      setAppTitle(
+        data.title.startsWith('"')
+          ? data.title.substring(1, data.title.length - 1)
+          : data.title
+      )
+    }
+  }, [data])
+
+  return (
+    <Typography
+      component="h1"
+      variant="h6"
+      color="inherit"
+      noWrap
+      sx={{ flexGrow: 1 }}
+    >
+      {appTitle.startsWith('"') ? appTitle.substring(1, appTitle.length - 1) : appTitle}
+    </Typography>
+  )
+}

frontend/src/components/subscriptions/SubscriptionsDialog.tsx

@@ -15,7 +15,7 @@ import {
   Typography
 } from '@mui/material'
 import { TransitionProps } from '@mui/material/transitions'
-import { matchW } from 'fp-ts/lib/Either'
+import { matchW } from 'fp-ts/lib/TaskEither'
 import { pipe } from 'fp-ts/lib/function'
 import { useAtomValue } from 'jotai'
 import { forwardRef, startTransition, useState } from 'react'
@@ -52,21 +52,16 @@ const SubscriptionsDialog: React.FC<Props> = ({ open, onClose }) => {
 
   const baseURL = useAtomValue(serverURL)
 
-  const submit = async (sub: Omit<Subscription, 'id'>) => {
+  const submit = async (sub: Omit<Subscription, 'id'>) => pipe(
-    const task = ffetch<void>(`${baseURL}/subscriptions`, {
+    ffetch<void>(`${baseURL}/subscriptions`, {
       method: 'POST',
       body: JSON.stringify(sub)
-    })
+    }),
-    const either = await task()
+    matchW(
-
+      (l) => pushMessage(l, 'error'),
-    pipe(
+      (_) => onClose()
-      either,
-      matchW(
-        (l) => pushMessage(l, 'error'),
-        (_) => onClose()
-      )
     )
-  }
+  )()
 
   return (
     <Dialog

frontend/src/hooks/useFetch.ts

@@ -6,6 +6,12 @@ import { serverURL } from '../atoms/settings'
 import { ffetch } from '../lib/httpClient'
 import { useToast } from './toast'
 
+/**
+ * Wrapper hook for ffetch. Handles data retrieval and cancellation signals.
+ * If R type is set to void it doesn't perform deserialization.
+ * @param resource path of the resource. serverURL is prepended
+ * @returns JSON decoded value, eventual error and refetcher as an object to destruct.
+ */
 const useFetch = <R>(resource: string) => {
   const base = useAtomValue(serverURL)
 
@@ -26,7 +32,10 @@ const useFetch = <R>(resource: string) => {
   )()
 
   useEffect(() => {
+    const controller = new AbortController()
     fetcher()
+
+    return () => controller.abort()
   }, [])
 
   return { data, error, fetcher }

frontend/src/lib/httpClient.ts

@@ -1,6 +1,9 @@
 import { tryCatch } from 'fp-ts/TaskEither'
+import * as J from 'fp-ts/Json'
+import * as E from 'fp-ts/Either'
+import { pipe } from 'fp-ts/lib/function'
 
-async function fetcher<T>(url: string, opt?: RequestInit): Promise<T> {
+async function fetcher(url: string, opt?: RequestInit, controller?: AbortController): Promise<string> {
   const jwt = localStorage.getItem('token')
 
   if (opt && !opt.headers) {
@@ -14,17 +17,25 @@ async function fetcher<T>(url: string, opt?: RequestInit): Promise<T> {
     headers: {
       ...opt?.headers,
       'X-Authentication': jwt ?? ''
-    }
+    },
+    signal: controller?.signal
   })
 
   if (!res.ok) {
     throw await res.text()
   }
 
-  return res.json() as T
+  return res.text()
 }
 
-export const ffetch = <T>(url: string, opt?: RequestInit) => tryCatch(
+export const ffetch = <T>(url: string, opt?: RequestInit, controller?: AbortController) => tryCatch(
-  () => fetcher<T>(url, opt),
+  async () => pipe(
+    await fetcher(url, opt, controller),
+    J.parse,
+    E.match(
+      (l) => l as T,
+      (r) => r as T
+    )
+  ),
   (e) => `error while fetching: ${e}`
 )

frontend/src/views/Settings.tsx

@@ -17,7 +17,9 @@ import {
   Typography,
   capitalize
 } from '@mui/material'
-import { useAtom } from 'jotai'
+import { pipe } from 'fp-ts/lib/function'
+import { matchW } from 'fp-ts/lib/TaskEither'
+import { useAtom, useAtomValue } from 'jotai'
 import { Suspense, useCallback, useEffect, useMemo, useState } from 'react'
 import {
   Subject,
@@ -34,9 +36,9 @@ import {
   accentState,
   accents,
   appTitleState,
+  autoFileExtensionState,
   enableCustomArgsState,
   fileRenamingState,
-  autoFileExtensionState,
   formatSelectionState,
   languageState,
   languages,
@@ -45,12 +47,14 @@ import {
   servedFromReverseProxySubDirState,
   serverAddressState,
   serverPortState,
+  serverURL,
   themeState
 } from '../atoms/settings'
 import CookiesTextField from '../components/CookiesTextField'
 import UpdateBinaryButton from '../components/UpdateBinaryButton'
 import { useToast } from '../hooks/toast'
 import { useI18n } from '../hooks/useI18n'
+import { ffetch } from '../lib/httpClient'
 import Translator from '../lib/i18n'
 import { validateDomain, validateIP } from '../utils'
 
@@ -70,7 +74,7 @@ export default function Settings() {
 
   const [pollingTime, setPollingTime] = useAtom(rpcPollingTimeState)
   const [language, setLanguage] = useAtom(languageState)
-  const [appTitle, setApptitle] = useAtom(appTitleState)
+  const [appTitle, setAppTitle] = useAtom(appTitleState)
   const [accent, setAccent] = useAtom(accentState)
 
   const [theme, setTheme] = useAtom(themeState)
@@ -81,7 +85,11 @@ export default function Settings() {
 
   const { pushMessage } = useToast()
 
+  // TODO: change name
+  const derivedServerURL = useAtomValue(serverURL)
+
   const baseURL$ = useMemo(() => new Subject<string>(), [])
+  const appTitle$ = useMemo(() => new Subject<string>(), [])
   const serverAddr$ = useMemo(() => new Subject<string>(), [])
   const serverPort$ = useMemo(() => new Subject<string>(), [])
 
@@ -134,6 +142,25 @@ export default function Settings() {
     return () => sub.unsubscribe()
   }, [])
 
+  // TODO: refactor out of component. maybe use withAtomEffect from jotai/effect package.
+  useEffect(() => {
+    const sub = appTitle$
+      .pipe(debounceTime(500))
+      .subscribe(title => {
+        pipe(
+          ffetch(`${derivedServerURL}/webconfig/title`, {
+            method: 'PATCH',
+            body: JSON.stringify(title)
+          }),
+          matchW(
+            (l) => pushMessage(l, 'error'),
+            (_) => setAppTitle(title)
+          )
+        )()
+      })
+    return () => sub.unsubscribe()
+  }, [])
+
   /**
    * Language toggler handler 
    */
@@ -194,7 +221,7 @@ export default function Settings() {
               fullWidth
               label={i18n.t('appTitle')}
               defaultValue={appTitle}
-              onChange={(e) => setApptitle(e.currentTarget.value)}
+              onChange={(e) => appTitle$.next(e.target.value)}
               error={appTitle === ''}
             />
           </Grid>
@@ -218,7 +245,7 @@ export default function Settings() {
                 { value: 500, label: '500 ms' },
                 { value: 750, label: '750 ms' },
                 { value: 1000, label: '1000 ms' },
-                { value: 2000, label: '2000 ms' },
+                { value: 2000, label: '2 s' },
               ]}
               onChange={(_, value) => typeof value === 'number'
                 ? setPollingTime(value)

server/archive/utils.go

@@ -0,0 +1,58 @@
+package archive
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/config"
+)
+
+// Perform a search on the archive.txt file an determines if a download
+// has already be done.
+func DownloadExists(ctx context.Context, url string) (bool, error) {
+	cmd := exec.CommandContext(
+		ctx,
+		config.Instance().DownloaderPath,
+		"--print",
+		"%(extractor)s %(id)s",
+		url,
+	)
+	stdout, err := cmd.Output()
+	if err != nil {
+		return false, err
+	}
+
+	extractorAndURL := bytes.Trim(stdout, "\n")
+
+	fd, err := os.Open(filepath.Join(config.Instance().Dir(), "archive.txt"))
+	if err != nil {
+		return false, err
+	}
+	defer fd.Close()
+
+	scanner := bufio.NewScanner(fd)
+
+	// search linearly for lower memory usage...
+	// the a pre-sorted with hashed values version of the archive.txt file can be loaded in memory
+	// and perform a binary search on it.
+	for scanner.Scan() {
+		if bytes.Equal(scanner.Bytes(), extractorAndURL) {
+			return true, nil
+		}
+	}
+
+	// data, err := io.ReadAll(fd)
+	// if err != nil {
+	// 	return false, err
+	// }
+
+	// slices.BinarySearchFunc(data, extractorAndURL, func(a []byte, b []byte) int {
+	// 	return hash(a).Compare(hash(b))
+	// })
+
+	return false, nil
+}

server/configurator/configurator.go

@@ -0,0 +1,104 @@
+package configurator
+
+import (
+	"log/slog"
+	"os"
+	"path/filepath"
+	"sync"
+
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/config"
+	"gopkg.in/yaml.v3"
+)
+
+// A singleton holding configuration of the frontend component
+// with optional persistence on a file.
+type AppConfig struct {
+	Title          string `yaml:"title" json:"title"`
+	BaseURL        string `yaml:"base_url" json:"base_url"`
+	Language       string `yaml:"language" json:"language"`
+	RPCPollingTime int    `yaml:"rpc_polling_time" json:"rpc_polling_time"`
+}
+
+type Configurator struct {
+	mu     sync.RWMutex
+	Config AppConfig
+}
+
+var (
+	instance     *Configurator
+	instanceOnce sync.Once
+)
+
+func Instance() *Configurator {
+	instanceOnce.Do(func() {
+		if instance == nil {
+			instance = &Configurator{}
+
+			// TODO: move out of initialization
+			err := instance.Load()
+			if err != nil {
+				slog.Error("failed initializating configurator", slog.Any("err", err))
+			}
+		}
+	})
+	return instance
+}
+
+func (c *Configurator) Load() error {
+	fd, err := getConfigurationFile()
+	if err != nil {
+		return err
+	}
+	defer fd.Close()
+
+	if err := yaml.NewDecoder(fd).Decode(&c.Config); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c *Configurator) Persist() error {
+	fd, err := getConfigurationFile()
+	if err != nil {
+		return err
+	}
+	defer fd.Close()
+
+	if err := yaml.NewEncoder(fd).Encode(c.Config); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c *Configurator) setAppConfig(ac *AppConfig) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	// TODO: better validaitons
+	if ac.BaseURL != "" {
+		c.Config.BaseURL = ac.BaseURL
+	}
+	if ac.Language != "" {
+		c.Config.Language = ac.Language
+	}
+	if ac.Title != "" {
+		c.Config.Title = ac.Title
+	}
+	if ac.RPCPollingTime >= 250 && ac.RPCPollingTime <= 2000 {
+		c.Config.RPCPollingTime = ac.RPCPollingTime
+	}
+}
+
+func getConfigurationFile() (*os.File, error) {
+	fd, err := os.OpenFile(
+		filepath.Join(config.Instance().Dir(), "web_config.yml"),
+		os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	return fd, nil
+}

server/configurator/handlers.go

@@ -0,0 +1,103 @@
+package configurator
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+)
+
+// App configurator REST handlers
+
+func GetConfig(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+
+	w.Header().Set("Content-Type", "application/json")
+
+	if err := json.NewEncoder(w).Encode(Instance().Config); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+}
+
+func SetConfig(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+
+	w.Header().Set("Content-Type", "application/json")
+
+	var req AppConfig
+
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	Instance().setAppConfig(&req)
+
+	if err := Instance().Persist(); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	json.NewEncoder(w).Encode("ok")
+}
+
+func setAppTitle(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+
+	w.Header().Set("Content-Type", "application/json")
+
+	var req string
+
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	editField(w, func(c *AppConfig) {
+		if req != "" {
+			c.Title = req
+		}
+	})
+
+	json.NewEncoder(w).Encode("ok")
+}
+
+func setBaseURL(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+
+	w.Header().Set("Content-Type", "application/json")
+
+	var req string
+
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	editField(w, func(c *AppConfig) {
+		if req != "" {
+			c.BaseURL = req
+		}
+	})
+
+	json.NewEncoder(w).Encode("ok")
+}
+
+func editField(w http.ResponseWriter, editFunc func(c *AppConfig)) {
+	editFunc(&Instance().Config)
+
+	if err := Instance().Persist(); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+}
+
+func ApplyRouter() func(r chi.Router) {
+	return func(r chi.Router) {
+		r.Get("/", GetConfig)
+		r.Post("/", SetConfig)
+		r.Patch("/title", setAppTitle)
+		r.Patch("/baseURL", setBaseURL)
+	}
+}

server/internal/livestream/monitor.go

@@ -76,7 +76,7 @@ func (m *Monitor) Status() LiveStreamStatus {
 // Persist the monitor current state to a file.
 // The file is located in the configured config directory
 func (m *Monitor) Persist() error {
-	fd, err := os.Create(filepath.Join(config.Instance().Dir(), "livestreams.dat"))
+	fd, err := os.Create(filepath.Join(config.Instance().SessionFilePath, "livestreams.dat"))
 	if err != nil {
 		return err
 	}
@@ -95,7 +95,7 @@ func (m *Monitor) Persist() error {
 
 // Restore a saved state and resume the monitored livestreams
 func (m *Monitor) Restore() error {
-	fd, err := os.Open(filepath.Join(config.Instance().Dir(), "livestreams.dat"))
+	fd, err := os.Open(filepath.Join(config.Instance().SessionFilePath, "livestreams.dat"))
 	if err != nil {
 		return err
 	}

server/internal/playlist.go

@@ -88,10 +88,10 @@ func PlaylistDetect(req DownloadRequest, mq *MessageQueue, db *MemoryDB) error {
 
 			proc.Info.URL = meta.URL
 
-			time.Sleep(time.Millisecond)
-
 			db.Set(proc)
 			mq.Publish(proc)
+
+			proc.Info.CreatedAt = meta.CreatedAt
 		}
 
 		return nil

server/server.go

@@ -22,6 +22,7 @@ import (
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/archive"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/archiver"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/config"
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/configurator"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/dbutil"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/filebrowser"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/internal"
@@ -235,6 +236,9 @@ func newServer(c serverConfig) *http.Server {
 	// Subscriptions
 	r.Route("/subscriptions", subscription.Container(c.db, cronTaskRunner).ApplyRouter())
 
+	// Frontend config store
+	r.Route("/webconfig", configurator.ApplyRouter())
+
 	return &http.Server{Handler: r}
 }
 

server/subscription/rest/handler.go

@@ -48,10 +48,7 @@ func (h *RestHandler) Delete() http.HandlerFunc {
 			return
 		}
 
-		if err := json.NewEncoder(w).Encode("ok"); err != nil {
+		w.WriteHeader(http.StatusOK)
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
 	}
 }
 

server/subscription/service/service.go

@@ -53,6 +53,7 @@ func toDB(dto *domain.Subscription) data.Subscription {
 
 // Delete implements domain.Service.
 func (s *Service) Delete(ctx context.Context, id string) error {
+	s.runner.StopTask(id)
 	return s.r.Delete(ctx, id)
 }
 

server/subscription/task/runner.go

@@ -7,9 +7,9 @@ import (
 	"os/exec"
 	"path/filepath"
 	"regexp"
-	"strings"
 	"time"
 
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/archive"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/config"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/internal"
 	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/subscription/domain"
@@ -19,10 +19,12 @@ import (
 type TaskRunner interface {
 	Submit(subcription *domain.Subscription) error
 	Spawner(ctx context.Context)
+	StopTask(id string) error
 	Recoverer()
 }
 
-type taskPair struct {
+type monitorTask struct {
+	Done         chan struct{}
 	Schedule     cron.Schedule
 	Subscription *domain.Subscription
 }
@@ -31,21 +33,22 @@ type CronTaskRunner struct {
 	mq *internal.MessageQueue
 	db *internal.MemoryDB
 
-	tasks  chan taskPair
+	tasks  chan monitorTask
 	errors chan error
+
+	running map[string]*monitorTask
 }
 
 func NewCronTaskRunner(mq *internal.MessageQueue, db *internal.MemoryDB) TaskRunner {
 	return &CronTaskRunner{
-		mq:     mq,
+		mq:      mq,
-		db:     db,
+		db:      db,
-		tasks:  make(chan taskPair),
+		tasks:   make(chan monitorTask),
-		errors: make(chan error),
+		errors:  make(chan error),
+		running: make(map[string]*monitorTask),
 	}
 }
 
-const commandTemplate = "-I1 --flat-playlist --print webpage_url $1"
-
 var argsSplitterRe = regexp.MustCompile(`(?mi)[^\s"']+|"([^"]*)"|'([^']*)'`)
 
 func (t *CronTaskRunner) Submit(subcription *domain.Subscription) error {
@@ -54,7 +57,8 @@ func (t *CronTaskRunner) Submit(subcription *domain.Subscription) error {
 		return err
 	}
 
-	job := taskPair{
+	job := monitorTask{
+		Done:         make(chan struct{}),
 		Schedule:     schedule,
 		Subscription: subcription,
 	}
@@ -64,54 +68,110 @@ func (t *CronTaskRunner) Submit(subcription *domain.Subscription) error {
 	return nil
 }
 
+// Handles the entire lifecylce of a monitor job.
 func (t *CronTaskRunner) Spawner(ctx context.Context) {
-	for task := range t.tasks {
+	for req := range t.tasks {
+		t.running[req.Subscription.Id] = &req // keep track of the current job
+
 		go func() {
+			ctx, cancel := context.WithCancel(ctx) // inject into the job's context a cancellation singal
+			fetcherEvents := t.doFetch(ctx, &req)  // retrieve the channel of events of the job
+
 			for {
-				slog.Info("fetching latest video for channel", slog.String("channel", task.Subscription.URL))
+				select {
-
+				case <-req.Done:
-				fetcherParams := strings.Split(strings.Replace(commandTemplate, "$1", task.Subscription.URL, 1), " ")
+					slog.Info("stopping cron job and removing schedule", slog.String("url", req.Subscription.URL))
-
+					cancel()
-				cmd := exec.CommandContext(
-					ctx,
-					config.Instance().DownloaderPath,
-					fetcherParams...,
-				)
-
-				stdout, err := cmd.Output()
-				if err != nil {
-					t.errors <- err
 					return
+				case <-fetcherEvents:
+					slog.Info("finished monitoring channel", slog.String("url", req.Subscription.URL))
 				}
-
-				latestChannelURL := string(bytes.Trim(stdout, "\n"))
-
-				p := &internal.Process{
-					Url: latestChannelURL,
-					Params: append(argsSplitterRe.FindAllString(task.Subscription.Params, 1), []string{
-						"--download-archive",
-						filepath.Join(config.Instance().Dir(), "archive.txt"),
-					}...),
-					AutoRemove: true,
-				}
-
-				t.db.Set(p)
-				t.mq.Publish(p)
-
-				nextSchedule := time.Until(task.Schedule.Next(time.Now()))
-
-				slog.Info(
-					"cron task runner next schedule",
-					slog.String("url", task.Subscription.URL),
-					slog.Any("duration", nextSchedule),
-				)
-
-				time.Sleep(nextSchedule)
 			}
 		}()
 	}
 }
 
-func (t *CronTaskRunner) Recoverer() {
+// Stop a currently scheduled job
-	panic("Unimplemented")
+func (t *CronTaskRunner) StopTask(id string) error {
+	task := t.running[id]
+	if task != nil {
+		t.running[id].Done <- struct{}{}
+		delete(t.running, id)
+	}
+	return nil
+}
+
+// Start a fetcher and notify on a channel when a fetcher has completed
+func (t *CronTaskRunner) doFetch(ctx context.Context, req *monitorTask) <-chan struct{} {
+	completed := make(chan struct{})
+
+	// generator func
+	go func() {
+		for {
+			sleepFor := t.fetcher(ctx, req)
+			completed <- struct{}{}
+
+			time.Sleep(sleepFor)
+		}
+	}()
+
+	return completed
+}
+
+// Perform the retrieval of the latest video of the channel.
+// Returns a time.Duration containing the amount of time to the next schedule.
+func (t *CronTaskRunner) fetcher(ctx context.Context, req *monitorTask) time.Duration {
+	slog.Info("fetching latest video for channel", slog.String("channel", req.Subscription.URL))
+
+	nextSchedule := time.Until(req.Schedule.Next(time.Now()))
+
+	cmd := exec.CommandContext(
+		ctx,
+		config.Instance().DownloaderPath,
+		"-I1",
+		"--flat-playlist",
+		"--print", "webpage_url",
+		req.Subscription.URL,
+	)
+
+	stdout, err := cmd.Output()
+	if err != nil {
+		t.errors <- err
+		return time.Duration(0)
+	}
+
+	latestVideoURL := string(bytes.Trim(stdout, "\n"))
+
+	// if the download exists there's not point in sending it into the message queue.
+	exists, err := archive.DownloadExists(ctx, latestVideoURL)
+	if exists && err == nil {
+		return nextSchedule
+	}
+
+	p := &internal.Process{
+		Url: latestVideoURL,
+		Params: append(
+			argsSplitterRe.FindAllString(req.Subscription.Params, 1),
+			[]string{
+				"--break-on-existing",
+				"--download-archive",
+				filepath.Join(config.Instance().Dir(), "archive.txt"),
+			}...),
+		AutoRemove: true,
+	}
+
+	t.db.Set(p)     // give it an id
+	t.mq.Publish(p) // send it to the message queue waiting to be processed
+
+	slog.Info(
+		"cron task runner next schedule",
+		slog.String("url", req.Subscription.URL),
+		slog.Any("duration", nextSchedule),
+	)
+
+	return nextSchedule
+}
+
+func (t *CronTaskRunner) Recoverer() {
+	panic("unimplemented")
 }