Sinjalizimi \u00ebsht\u00eb ngusht\u00ebsisht i lidhur me realizimin ton\u00eb t\u00eb soket\u00ebve, t\u00eb p\u00ebrshkruar n\u00eb seksionin n\u00eb vijim.<\/li>\n<\/ul>\n\nLista e server\u00ebve brenda loj\u00ebs dhe n\u00eb faqen kryesore<\/i><\/p>\nRealizimi i soket\u00ebve<\/h1>\n
\nNe duam t\u00eb krijojm\u00eb nj\u00eb API sa m\u00eb t\u00eb af\u00ebrt me Posix UDP Sockets, p\u00ebr t\u00eb minimizuar numrin e ndryshimeve t\u00eb nevojshme.<\/p>\n
Po ashtu, ne d\u00ebshirojm\u00eb t\u00eb realizojm\u00eb minimumin e nevojsh\u00ebm p\u00ebr shk\u00ebmbimin m\u00eb t\u00eb thjesht\u00eb t\u00eb t\u00eb dh\u00ebnave p\u00ebrmes rrjetit.<\/p>\n
P\u00ebr shembull, ne nuk kemi nevoj\u00eb p\u00ebr rrug\u00ebzim t\u00eb v\u00ebrtet\u00eb: t\u00eb gjith\u00eb peer\u00ebt ndodhen n\u00eb nj\u00eb \u2018LAN virtuale\u2019, t\u00eb lidhur me nj\u00eb instanc\u00eb specifike t\u00eb baz\u00ebs s\u00eb t\u00eb dh\u00ebnave Firebase.<\/p>\n
Prandaj, ne nuk kemi nevoj\u00eb p\u00ebr adresa IP unike: p\u00ebr identifikimin unik t\u00eb peer\u00ebve mjafton t\u00eb p\u00ebrdorim vlerat unike t\u00eb \u00e7el\u00ebsave t\u00eb Firebase (n\u00eb analogji me emrat e domain-it), dhe \u00e7do peer cakton lokal \u2018adresa IP t\u00eb rreme\u2019 \u00e7do \u00e7el\u00ebsi q\u00eb duhet t\u00eb konvertohet. Kjo na \u00e7liron plot\u00ebsisht nga nevoja p\u00ebr caktimin global t\u00eb adresave IP, q\u00eb \u00ebsht\u00eb nj\u00eb detyr\u00eb jo triviale.<\/p>\n
Ja API minimale q\u00eb na nevojitet t\u00eb realizojm\u00eb:<\/p>\n
\/\/ Create and destroy a socket\nint socket();\nint close(int fd);\n\/\/ Bind a socket to a port, and publish it on Firebase\nint bind(int fd, AddrInfo* addr);\n\/\/ Send a packet. This lazily create a WebRTC connection to the \n\/\/ peer when necessary\nint sendto(int fd, uint8_t* buf, int len, const AddrInfo* addr);\n\/\/ Receive the packets destined to this socket\nint recvfrom(int fd, uint8_t* buf, int len, AddrInfo* addr);\n\/\/ Be notified when new packets arrived\nint recvCallback(Callback cb);\n\/\/ Obtain a local ip address for this peer key\nuint32_t resolve(client::String* key);\n\/\/ Get the peer key for this ip\nString* reverseResolve(uint32_t addr);\n\/\/ Get the local peer key\nString* local_key();\n\/\/ Initialize the library with the given Firebase database and \n\/\/ WebRTc connection options\nvoid init(client::FirebaseConfig* fb, client::RTCConfiguration* ice);<\/code><\/pre>\n\nAPI \u00ebsht\u00eb i thjesht\u00eb dhe ngjan me API-n\u00eb e Soket\u00ebve Posix, por ka disa dallime t\u00eb r\u00ebnd\u00ebsishme: regjistrimi i thirrjeve t\u00eb prapave, caktimi i IP-ve lokale dhe \u2018lidhja e ngadalt\u00eb\u2019<\/strong>.<\/p>\nRegjistrimi i thirrjeve t\u00eb prapave<\/h2>\n \nEdhe n\u00ebse programi origjinal p\u00ebrdor hyrje-dalje jo bllokuese, p\u00ebr ta ekzekutuar n\u00eb shfletuesin e internetit, kodi duhet t\u00eb ristrukturohet.<\/p>\n
Arsyeja p\u00ebr k\u00ebt\u00eb \u00ebsht\u00eb se cikli i ngjarjeve n\u00eb shfletues \u00ebsht\u00eb i fshehur nga programi (qoft\u00eb JavaScript ose WebAssembly).<\/p>\n
N\u00eb mjedisin natyror, ne mund t\u00eb shkruajm\u00eb kod n\u00eb k\u00ebt\u00eb m\u00ebnyr\u00eb<\/p>\n
while(running) {\n select(...); \/\/ prisni p\u00ebr ngjarjet I\/O\n while(true) {\n int r = readfrom(...); \/\/ provoni t\u00eb lexoni\n if (r < 0 && errno == EWOULDBLOCK) \/\/ nuk ka m\u00eb t\u00eb dh\u00ebna t\u00eb disponueshme\n break;\n ...\n }\n ...\n}<\/code><\/pre>\n\nN\u00ebse cikli i ngjarjeve \u00ebsht\u00eb i fshehur nga ne, duhet ta kthejm\u00eb at\u00eb n\u00eb di\u00e7ka t\u00eb till\u00eb:<\/p>\n
auto cb = []() { \/\/ kjo do t\u00eb thirret kur t\u00eb dh\u00ebnat e reja t\u00eb jen\u00eb t\u00eb disponueshme\n while(true) {\n int r = readfrom(...); \/\/ provoni t\u00eb lexoni\n if (r < 0 && errno == EWOULDBLOCK) \/\/ nuk ka m\u00eb t\u00eb dh\u00ebna t\u00eb disponueshme\n break;\n ...\n }\n ...\n};\nrecvCallback(cb); \/\/ regjistro thirrjen e prapave<\/code><\/pre>\n<\/p>\n
Q\u00ebllimi i IP-ve lokale<\/h2>\n \nIdentifikuesit e node-ve n\u00eb \"rrjetin\" ton\u00eb nuk jan\u00eb adresa IP, por \u00e7el\u00ebsa Firebase (kjo jan\u00eb vargje q\u00eb duken k\u00ebshtu: -LmEC50PYZLCiCP-vqde<\/code> ).<\/p>\nKjo \u00ebsht\u00eb e dobishme sepse nuk na nevojitet nj\u00eb mekaniz\u00ebm p\u00ebr caktimin e IP-ve dhe verifikimin e unikalitetit t\u00eb tyre (po ashtu dhe p\u00ebr riciklimin e tyre pas \u00e7aktivizimit t\u00eb klientit), por shpesh \u00ebsht\u00eb e nevojshme t\u00eb identifikosh peer-et n\u00eb baz\u00eb t\u00eb nj\u00eb vler\u00ebs numerike.<\/p>\n
Pik\u00ebrisht p\u00ebr k\u00ebt\u00eb p\u00ebrdoren funksionet resolve<\/code> dhe reverseResolve<\/code>: aplikacioni n\u00eb nj\u00eb m\u00ebnyr\u00eb merr vler\u00ebn string t\u00eb \u00e7el\u00ebsit (n\u00ebp\u00ebrmjet hyrjes s\u00eb p\u00ebrdoruesit ose p\u00ebrmes serverit kryesor), dhe mund ta konvertoj\u00eb at\u00eb n\u00eb nj\u00eb adres\u00eb IP p\u00ebr p\u00ebrdorim t\u00eb brendsh\u00ebm. Pjesa tjet\u00ebr e API gjithashtu p\u00ebr thjesht\u00ebsi merr k\u00ebt\u00eb vler\u00eb n\u00eb vend t\u00eb vargut.<\/p>\nKjo \u00ebsht\u00eb e ngjashme me k\u00ebrkimin DNS, vet\u00ebm se kryhet lokalisht te klienti.<\/p>\n
K\u00ebshtu q\u00eb adresat IP nuk mund t\u00eb jen\u00eb t\u00eb zakonshme p\u00ebr klient\u00eb t\u00eb ndrysh\u00ebm, dhe n\u00ebse nevojitet nj\u00eb identifikues global, at\u00ebher\u00eb do t\u00eb duhet t\u00eb gjenerohet n\u00eb nj\u00eb m\u00ebnyr\u00eb tjet\u00ebr.<\/p>\n
Koneksioni lenv\u00eb<\/h2>\n \nUDP nuk k\u00ebrkon nj\u00eb lidhje, por, si\u00e7 pam\u00eb, p\u00ebrpara se t\u00eb filloj\u00eb kalimi i t\u00eb dh\u00ebnave mes dy peer-\u00ebve, WebRTC k\u00ebrkon nj\u00eb proces t\u00eb gjat\u00eb lidhjeje.<\/p>\n
N\u00ebse duam t\u00eb sigurojm\u00eb t\u00eb nj\u00ebjtin nivel abstrahimi, (sendto<\/code>\/recvfrom<\/code> me peer t\u00eb rast\u00ebsish\u00ebm pa lidhje paraprake), at\u00ebher\u00eb duhet t\u00eb kryejm\u00eb nj\u00eb lidhje \"lenva\" n\u00eb brend\u00ebsi t\u00eb API.<\/p>\nKjo \u00ebsht\u00eb ajo q\u00eb ndodh gjat\u00eb shk\u00ebmbimit t\u00eb zakonsh\u00ebm t\u00eb t\u00eb dh\u00ebnave mes \"serverit\" dhe \"klientit\" n\u00eb rastin e p\u00ebrdorimit t\u00eb UDP, dhe \u00e7far\u00eb duhet t\u00eb realizoj\u00eb biblioteka jon\u00eb:<\/p>\n
\nServeri th\u00ebrret bind()<\/code>, p\u00ebr t\u00eb informuar sistemin operativ se d\u00ebshiron t\u00eb marr\u00eb paketa n\u00eb portin e caktuar.<\/li>\n<\/ul>\n\nN\u00eb vend t\u00eb k\u00ebsaj, ne do t\u00eb publikojm\u00eb nj\u00eb port t\u00eb hapur n\u00eb Firebase n\u00ebn \u00e7el\u00ebsin e serverit dhe do t\u00eb d\u00ebgjojm\u00eb ngjarjet n\u00eb n\u00ebnpjes\u00ebn e tij.<\/p>\n
\nServeri th\u00ebrret recvfrom()<\/code>, duke pranuar n\u00eb k\u00ebt\u00eb port paketa q\u00eb vijn\u00eb nga \u00e7do host.<\/li>\n<\/ul>\n\nN\u00eb rastin ton\u00eb, duhet t\u00eb kontrollojm\u00eb radh\u00ebn hyr\u00ebse t\u00eb paketimeve t\u00eb d\u00ebrguara n\u00eb k\u00ebt\u00eb port.<\/p>\n
\u00c7do port ka radh\u00ebn e tij t\u00eb vetme, dhe ne shtojm\u00eb n\u00eb fillim t\u00eb datagram\u00ebve WebRTC portet burimore dhe t\u00eb fundit, n\u00eb m\u00ebnyr\u00eb q\u00eb t\u00eb dim\u00eb se n\u00eb cil\u00ebn radh\u00eb t\u00eb riorientojm\u00eb kur arrin nj\u00eb paket\u00eb t\u00eb re.<\/p>\n
Thirrja \u00ebsht\u00eb jo-bllokuese, k\u00ebshtu q\u00eb n\u00ebse nuk ka paketa, ne thjesht kthejm\u00eb -1 dhe caktojm\u00eb errno=EWOULDBLOCK<\/code>.<\/p>\n\nKlienti merr n\u00ebp\u00ebrmjet mjeteve t\u00eb jashtme IP-n\u00eb dhe portin e serverit, dhe th\u00ebrret sendto()<\/code>. Po ashtu, gjat\u00eb k\u00ebsaj kryhet nj\u00eb thirrje e brendshme bind()<\/code>, k\u00ebshtu q\u00eb thirrja e m\u00ebpasshme recvfrom()<\/code> do t\u00eb marr\u00eb p\u00ebrgjigje pa ekzekutimin e qart\u00eb t\u00eb bind.<\/li>\n<\/ul>\n\nN\u00eb rastin ton\u00eb, klienti merr n\u00eb m\u00ebnyr\u00eb t\u00eb jashtme nj\u00eb \u00e7el\u00ebs string dhe p\u00ebrdor funksionin resolve()<\/code> p\u00ebr t\u00eb marr\u00eb adres\u00ebn IP.<\/p>\nN\u00eb k\u00ebt\u00eb faz\u00eb, ne fillojm\u00eb \"d\u00ebshirat\" WebRTC, n\u00ebse dy peer nuk jan\u00eb ende t\u00eb lidhur me nj\u00ebri-tjetrin. Koneksionet n\u00eb porte t\u00eb ndryshme t\u00eb nj\u00eb peer p\u00ebrdorin t\u00eb nj\u00ebjtin DataChannel WebRTC.<\/p>\n
Po ashtu ne kryejm\u00eb nj\u00eb t\u00ebrheqje bind()<\/code>, p\u00ebr t'i mund\u00ebsuar serverit t\u00eb rikthej\u00eb lidhjen n\u00eb sendto()<\/code> rast se ajo u mbyll p\u00ebr ndonj\u00eb arsye t\u00eb caktuar.<\/p>\nServeri njoftohet p\u00ebr lidhjen e klientit kur klienti regjistron ofert\u00ebn e tij SDP n\u00ebn informacionin e port\u00ebs s\u00eb serverit n\u00eb Firebase, dhe serveri p\u00ebrgjigjet me p\u00ebrgjigjen e tij atje.<\/p>\n
\nN\u00eb diagramin e treguar m\u00eb posht\u00eb, nj\u00eb shembull i l\u00ebvizjes s\u00eb mesazheve p\u00ebr skem\u00ebn e soketeve dhe d\u00ebrgimin nga klienti n\u00eb server t\u00eb mesazhit t\u00eb par\u00eb \u00ebsht\u00eb paraqitur:<\/p>\n
Diagrami i plot\u00eb i faz\u00ebs s\u00eb lidhjes midis klientit dhe serverit<\/i><\/p>\nP\u00ebrfundim<\/h1>\n
\nN\u00ebse e keni lexuar deri n\u00eb fund, ndoshta jeni t\u00eb interesuar t\u00eb shihni teorin\u00eb n\u00eb veprim. Mund t\u00eb luani n\u00eb teeworlds.leaningtech.com<\/a><\/noindex>, provoni!<\/p>\n