Costruire un Clone Slack in React con Parse e Live Query

app clone di slack in react introduzione in questa guida, continueremo a esplorare il parse react hook parse react hook in situazioni utili creando un'app clone di slack l'app avrà funzionalità di base come registrazione/accesso, canali e chat in tempo reale inoltre, i componenti react evidenziano l'utilità delle notifiche in tempo reale utilizzando live query, capacità di gestione degli utenti e la flessibilità di eseguire query (relazionali) in qualsiasi momento puoi rapidamente distribuire un'app clone di slack su vercel requisiti per completare questo tutorial, avrai bisogno di un account gratuito di back4app clona o scarica questo progetto tramite i nostri repository github in modo da poterlo eseguire insieme alla guida assicurati di seguire le istruzioni nel file readme per configurarlo correttamente nel tuo ambiente locale repository di esempio javascript repository di esempio typescript obiettivo costruire un'applicazione clone di slack in react utilizzando il @parse/react @parse/react hook 1 creare la tua app parse da un modello questa applicazione comprende due classi di database canale canale e messaggio messaggio , contenenti puntatori alla classe utente di parse invece di creare l'app e le classi di database da zero, cloniamo un modello esistente su back4app database hub clicca sul pulsante “clona database” e procedi con l'accesso e la creazione della tua app per ulteriori dettagli su come clonare, controlla la guida alla clonazione dell'app ora la tua app ha la struttura backend completa necessaria per creare il tuo slack clone su back4app 2 abilitare live query ora che hai creato l'app e le classi, devi abilitare la live query (in tempo reale) vai al tuo dashboard di back4app e naviga su impostazioni app impostazioni app > impostazioni server impostazioni server > url server e live query url server e live query dopo aver attivato il tuo sottodominio back4app, puoi quindi attivare la live query selezionando le classi messaggio messaggio e canale canale dopo di che, salva le modifiche l'url sopra è il tuo url live query url live query assicurati di copiarlo per inizializzare correttamente il hook di parse immergiamoci ora nei componenti principali di react channellist channellist , messagelist messagelist , e home home 3 i componenti della lista il channellist channellist e messagelist messagelist i componenti utilizzano il @parse/react @parse/react hook per recuperare i dati dell'utente tramite live query hanno la stessa struttura di pattern come nella guida react livechat https //www back4app com/docs/react/real time/react chat app vengono istanziati con parametri iniziali (recuperati tramite l' props props oggetto) che compongono dinamicamente la loro query live query dai un'occhiata alle loro query e a come le classi sono correlate tra loro javascript 1 // note that parse object coming from props need to be changed into pointers 2 // to be able to be used by parse, since react changes the object structure 3 // when passing down parameters to child components 4&#x9; 5 // channellist js 6&#x9; 7 const ownerquery = new parse query("channel"); 8 ownerquery equalto("owner", props currentuser topointer()); 9 const membersquery = new parse query("channel"); 10 membersquery containedin("members", \[props currentuser topointer()]); 11 // creates the or query 12 const parsequery = parse query or(ownerquery, membersquery); 13 // set results ordering 14 parsequery ascending("name"); 15 // include all pointer fields 16 parsequery includeall(); 17&#x9; 18 // messagelist js 19&#x9; 20 const parsequery = new parse query("message"); 21 // get messages that involve both nicknames 22 parsequery equalto("channel", props currentchannel topointer()); 23 // set results ordering 24 parsequery ascending("createdat"); 25 // include nickname fields, to enable name getting on list 26 parsequery includeall();1 // note that parse object coming from props need to be changed into pointers 2 // to be able to be used by parse, since react changes the object structure 3 // when passing down parameters to child components 4&#x9; 5 // channellist tsx 6&#x9; 7 // this query is a composite or one, combining the results of both 8 const ownerquery parse query = new parse query("channel"); 9 ownerquery equalto("owner", props currentuser topointer()); 10 const membersquery parse query = new parse query("channel"); 11 membersquery containedin("members", \[props currentuser topointer()]); 12 // creates the or query 13 const parsequery parse query = parse query or(ownerquery, membersquery); 14 // set results ordering 15 parsequery ascending("name"); 16 // include all pointer fields 17 parsequery includeall(); 18&#x9; 19 // messagelist tsx 20&#x9; 21 const parsequery parse query = new parse query("message"); 22 // get messages that involve both nicknames 23 parsequery equalto("channel", props currentchannel topointer()); 24 // set results ordering 25 parsequery ascending("createdat"); 26 // include nickname fields, to enable name getting on list 27 parsequery includeall(); queste query verranno eseguite ogni volta che ci sono cambiamenti nei dati delle classi, quindi se un altro utente nel canale invia un messaggio, lo vedrai apparire lì in tempo reale 4 il componente home il home home componente funge da schermo principale dell'applicazione, in cui i componenti della lista vengono renderizzati e istanziati condizionatamente quando necessario puoi trovare qui sotto il codice del componente dai un'occhiata alle funzioni per creare canali e invitare gli utenti a essi home js 1 import react, { useeffect, usestate } from "react"; 2 import " /app css"; 3 import { modal } from "antd"; 4 import { usehistory } from "react router dom"; 5 import parse from "parse"; 6 import { channellist } from " /channellist"; 7 import { messagelist } from " /messagelist"; 8 import { memberlist } from " /memberlist"; 9&#x9; 10 export const home = () => { 11 const history = usehistory(); 12&#x9; 13 // state variables holding input values and flags 14 const \[currentuser, setcurrentuser] = usestate(null); 15 const \[iscreatechannelmodalvisible, setiscreatechannelmodalvisible] = 16 usestate(false); 17 const \[createchannelinput, setcreatechannelinput] = usestate(""); 18 const \[currentchannel, setcurrentchannel] = usestate(null); 19&#x9; 20 // this effect hook runs at every render and checks if there is a 21 // logged in user, redirecting to login screen if needed 22 useeffect(() => { 23 const checkcurrentuser = async () => { 24 try { 25 const user = await parse user currentasync(); 26 if (user === null || user === undefined) { 27 history push("/"); 28 } else { 29 if (currentuser === null) { 30 setcurrentuser(user); 31 } 32 } 33 return true; 34 } catch ( error) {} 35 return false; 36 }; 37 checkcurrentuser(); 38 }); 39&#x9; 40 // logout function 41 const dologout = async () => { 42 // logout 43 try { 44 await parse user logout(); 45 // force useeffect execution to redirect back to login 46 setcurrentuser(null); 47 return true; 48 } catch (error) { 49 alert(error); 50 return false; 51 } 52 }; 53&#x9; 54 // makes modal visible 55 const showcreatechannelmodal = () => { 56 setiscreatechannelmodalvisible(true); 57 }; 58&#x9; 59 // clear input and hide modal on cancel 60 const handlecreatechannelmodalcancel = () => { 61 setcreatechannelinput(""); 62 setiscreatechannelmodalvisible(false); 63 }; 64&#x9; 65 // creates a channel based on input from modal 66 const docreatechannel = async () => { 67 const channelname = createchannelinput; 68&#x9; 69 if (channelname === "") { 70 alert("please inform your new channel name!"); 71 return false; 72 } 73&#x9; 74 // creates a new parse object instance and set parameters 75 const channel = new parse object("channel"); 76 channel set("name", channelname); 77 channel set("owner", currentuser); 78 // members is an array of parse user objects, so add() should be used to 79 // concatenate the value inside the array 80 channel add("members", currentuser); 81&#x9; 82 // clears input value and hide modal 83 setcreatechannelinput(""); 84 setiscreatechannelmodalvisible(false); 85&#x9; 86 try { 87 // save object on parse server 88 const saveresult = await channel save(); 89 // set the created channel as the active channel, 90 // showing the message list for this channel 91 setcurrentchannel(saveresult); 92 alert(`success on creating channel ${channelname}`); 93 return true; 94 } catch (error) { 95 alert(error); 96 return false; 97 } 98 }; 99&#x9; 100 // changes the active channel and shows the message list for it 101 // this is called using a callback in the channellist component 102 const doselectchannel = (channel) => { 103 setcurrentchannel(null); 104 setcurrentchannel(channel); 105 }; 106&#x9; 107 // settings current channel to null hides the message list component 108 // this is called using a callback in the messagelist component 109 const doclearcurrentchannel = () => { 110 setcurrentchannel(null); 111 }; 112&#x9; 113 return ( 114 \<div classname="grid"> 115 \<div classname="organizations"> 116 \<div classname="organization"> 117 \<picture classname="organization picture"> 118 \<img 119 classname="organization img" 120 src="https //scontent fsqx1 1 fna fbcdn net/v/t1 6435 9/29136314 969639596535770 8356900498426560512 n png? nc cat=103\&ccb=1 5& nc sid=973b4a& nc ohc=d9actpsb8duax zaa7f& nc ht=scontent fsqx1 1 fna\&oh=96679a09c5c4524f0a6c86110de697b6\&oe=618525f9" 121 alt="" 122 /> 123 \</picture> 124 \<p classname="organization title">back4app\</p> 125 \</div> 126 \<button classname="button inline" onclick={dologout}> 127 \<svg 128 classname="button inline icon" 129 xmlns="http //www w3 org/2000/svg" 130 width="24" 131 height="24" 132 viewbox="0 0 24 24" 133 fill="none" 134 stroke="currentcolor" 135 strokewidth="2" 136 strokelinecap="round" 137 strokelinejoin="round" 138 > 139 \<polyline points="9 10 4 15 9 20">\</polyline> 140 \<path d="m20 4v7a4 4 0 0 1 4 4h4">\</path> 141 \</svg> 142 \<span classname="button inline label">log out\</span> 143 \</button> 144 \</div> 145 \<div classname="channels"> 146 {/ action buttons (new channel and logout) /} 147 \<div> 148 \<modal 149 title="create new channel" 150 visible={iscreatechannelmodalvisible} 151 onok={docreatechannel} 152 oncancel={handlecreatechannelmodalcancel} 153 oktext={"create"} 154 > 155 <> 156 \<label>{"channel name"}\</label> 157 \<input 158 type={"text"} 159 value={createchannelinput} 160 placeholder={"new channel name"} 161 onchange={(event) => setcreatechannelinput(event target value)} 162 >\</input> 163 \</> 164 \</modal> 165 \</div> 166 \<div classname="channels header" onclick={showcreatechannelmodal}> 167 \<p classname="channels header label">channels\</p> 168 \<svg 169 classname="channels header icon" 170 xmlns="http //www w3 org/2000/svg" 171 height="24px" 172 viewbox="0 0 24 24" 173 width="24px" 174 fill="#000000" 175 > 176 \<path d="m0 0h24v24h0z" fill="none" /> 177 \<path d="m19 13h 6v6h 2v 6h5v 2h6v5h2v6h6v2z" /> 178 \</svg> 179 \</div> 180 {/ channel list component, instantiated only when the user is successfully fetched /} 181 {currentuser !== null && ( 182 \<channellist 183 currentuser={currentuser} 184 selectchannelcallback={doselectchannel} 185 /> 186 )} 187 \</div> 188 \<div classname="messages"> 189 {/ message list component, instantiated only when there is a selected channel /} 190 {currentuser !== null && currentchannel !== null && ( 191 \<messagelist 192 currentuser={currentuser} 193 currentchannel={currentchannel} 194 closechannelcallback={doclearcurrentchannel} 195 /> 196 )} 197 \</div> 198 \<div classname="info"> 199 {/ member list component, instantiated only when there is a selected channel /} 200 {currentuser !== null && currentchannel !== null && ( 201 \<memberlist 202 currentuser={currentuser} 203 currentchannel={currentchannel} 204 closechannelcallback={doclearcurrentchannel} 205 /> 206 )} 207 \</div> 208 \</div> 209 ); 210 }; home tsx 1 import react, { useeffect, usestate, fc, reactelement } from 'react'; 2 import ' /app css'; 3 import { modal } from 'antd'; 4 import { usehistory } from 'react router dom'; 5 import parse from 'parse'; 6 import { channellist } from ' /channellist'; 7 import { messagelist } from ' /messagelist'; 8 import { memberlist } from ' /memberlist'; 9&#x9; 10 export const home fc<{}> = () reactelement => { 11 const history = usehistory(); 12&#x9; 13 // state variables holding input values and flags 14 const \[currentuser, setcurrentuser] = usestate\<parse user | null>(null); 15 const \[iscreatechannelmodalvisible, setiscreatechannelmodalvisible] = usestate(false); 16 const \[createchannelinput, setcreatechannelinput] = usestate(''); 17 const \[currentchannel, setcurrentchannel] = usestate\<parse object | null>(null); 18&#x9; 19 // this effect hook runs at every render and checks if there is a 20 // logged in user, redirecting to login screen if needed 21 useeffect(() => { 22 const checkcurrentuser = async () promise\<boolean> => { 23 try { 24 const user (parse user | null) = await parse user currentasync(); 25 if (user === null || user === undefined) { 26 history push('/'); 27 } else { 28 if (currentuser === null) { 29 setcurrentuser(user); 30 } 31 } 32 return true; 33 } catch ( error any) {} 34 return false; 35 } 36 checkcurrentuser(); 37 }); 38&#x9; 39 // logout function 40 const dologout = async () promise\<boolean> => { 41 // logout 42 try { 43 await parse user logout(); 44 // force useeffect execution to redirect back to login 45 setcurrentuser(null); 46 return true; 47 } catch (error any) { 48 alert(error); 49 return false; 50 } 51 }; 52&#x9; 53 // makes modal visible 54 const showcreatechannelmodal = () void => { 55 setiscreatechannelmodalvisible(true); 56 } 57&#x9; 58 // clear input and hide modal on cancel 59 const handlecreatechannelmodalcancel = () void => { 60 setcreatechannelinput(""); 61 setiscreatechannelmodalvisible(false); 62 } 63&#x9; 64 // creates a channel based on input from modal 65 const docreatechannel = async () promise\<boolean> => { 66 const channelname string = createchannelinput; 67 68 if (channelname === '') { 69 alert("please inform your new channel name!"); 70 return false; 71 } 72&#x9; 73 // creates a new parse object instance and set parameters 74 const channel parse object = new parse object("channel"); 75 channel set('name', channelname); 76 channel set('owner', currentuser); 77 // members is an array of parse user objects, so add() should be used to 78 // concatenate the value inside the array 79 channel add('members', currentuser); 80&#x9; 81 // clears input value and hide modal 82 setcreatechannelinput(""); 83 setiscreatechannelmodalvisible(false); 84&#x9; 85 try { 86 // save object on parse server 87 const saveresult parse object = await channel save(); 88 // set the created channel as the active channel, 89 // showing the message list for this channel 90 setcurrentchannel(saveresult); 91 alert(`success on creating channel ${channelname}`); 92 return true; 93 } catch (error any) { 94 alert(error); 95 return false; 96 } 97 } 98&#x9; 99 // changes the active channel and shows the message list for it 100 // this is called using a callback in the channellist component 101 const doselectchannel = (channel parse object) void => { 102 setcurrentchannel(null); 103 setcurrentchannel(channel); 104 } 105&#x9; 106 // settings current channel to null hides the message list component 107 // this is called using a callback in the messagelist component 108 const doclearcurrentchannel = () void => { 109 setcurrentchannel(null); 110 } 111&#x9; 112 return ( 113 \<div classname="grid"> 114 \<div classname="organizations"> 115 \<div classname="organization"> 116 \<picture classname="organization picture"> 117 \<img classname="organization img" src="https //scontent fsqx1 1 fna fbcdn net/v/t1 6435 9/29136314 969639596535770 8356900498426560512 n png? nc cat=103\&ccb=1 5& nc sid=973b4a& nc ohc=d9actpsb8duax zaa7f& nc ht=scontent fsqx1 1 fna\&oh=96679a09c5c4524f0a6c86110de697b6\&oe=618525f9" alt="" /> 118 \</picture> 119 \<p classname="organization title">back4app\</p> 120 \</div> 121 \<button classname="button inline" onclick={dologout}> 122 \<svg classname="button inline icon" xmlns="http //www w3 org/2000/svg" width="24" height="24" viewbox="0 0 24 24" fill="none" stroke="currentcolor" strokewidth="2" strokelinecap="round" strokelinejoin="round">\<polyline points="9 10 4 15 9 20">\</polyline>\<path d="m20 4v7a4 4 0 0 1 4 4h4">\</path>\</svg> 123 \<span classname="button inline label">log out\</span> 124 \</button> 125 \</div> 126 \<div classname="channels"> 127 {/ action buttons (new channel and logout) /} 128 \<div> 129 \<modal 130 title="create new channel" 131 visible={iscreatechannelmodalvisible} 132 onok={docreatechannel} 133 oncancel={handlecreatechannelmodalcancel} 134 oktext={'create'} 135 > 136 <> 137 \<label>{'channel name'}\</label> 138 \<input 139 type={"text"} 140 value={createchannelinput} 141 placeholder={"new channel name"} 142 onchange={(event) => setcreatechannelinput(event target value)} 143 >\</input> 144 \</> 145 \</modal> 146 \</div> 147 \<div classname="channels header" onclick={showcreatechannelmodal}> 148 \<p classname="channels header label">channels\</p> 149 \<svg classname="channels header icon" xmlns="http //www w3 org/2000/svg" height="24px" viewbox="0 0 24 24" width="24px" fill="#000000">\<path d="m0 0h24v24h0z" fill="none"/>\<path d="m19 13h 6v6h 2v 6h5v 2h6v5h2v6h6v2z"/>\</svg> 150 \</div> 151 {/ channel list component, instantiated only when the user is successfully fetched /} 152 {currentuser !== null && ( 153 \<channellist 154 currentuser={currentuser} 155 selectchannelcallback={doselectchannel} 156 /> 157 )} 158 \</div> 159 \<div classname="messages"> 160 {/ message list component, instantiated only when there is a selected channel /} 161 {currentuser !== null && currentchannel !== null && ( 162 \<messagelist 163 currentuser={currentuser} 164 currentchannel={currentchannel} 165 closechannelcallback={doclearcurrentchannel} 166 /> 167 )} 168 \</div> 169 \<div classname="info"> 170 {/ member list component, instantiated only when there is a selected channel /} 171 {currentuser !== null && currentchannel !== null && ( 172 \<memberlist 173 currentuser={currentuser} 174 currentchannel={currentchannel} 175 closechannelcallback={doclearcurrentchannel} 176 /> 177 )} 178 \</div> 179 \</div> 180 ); 181 }; questo approccio di istanziare dinamicamente i componenti live query ci consente di riutilizzarli ogni volta che l'utente cambia il canale attivo, ne crea uno nuovo, invia un messaggio, ecc ecco come apparirà l'app completa 5 distribuisci su vercel in qualsiasi momento puoi distribuire l'applicazione su vercel facendo clic sul link qui sotto assicurati di avere il tuo application id application id , client key client key e livequery url livequery url per le chiavi puoi andare su impostazioni app impostazioni app > sicurezza e chiavi sicurezza e chiavi e poi copiare per il live query url live query url puoi andare al passo 2 e copiarlo conclusione alla fine di questa guida, hai appreso di più sull'uso del hook parse react per le query in tempo reale in parse e su come utilizzare il database hub di back4app