Sinjalizimi \u00ebsht\u00eb ngusht\u00ebsisht i lidhur me realizimin ton\u00eb t\u00eb socket-eve, 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 socket-eve<\/h1>\n
\nD\u00ebshirojm\u00eb t\u00eb krijojm\u00eb nj\u00eb API sa m\u00eb af\u00ebr socket-eve UDP Posix, p\u00ebr t\u00eb minimizuar numrin e ndryshimeve t\u00eb nevojshme.<\/p>\n
Po ashtu, duam t\u00eb zbatojm\u00eb minimumin e nevojsh\u00ebm q\u00eb k\u00ebrkohet p\u00ebr shk\u00ebmbimin m\u00eb t\u00eb thjesht\u00eb t\u00eb t\u00eb dh\u00ebnave n\u00eb rrjet.<\/p>\n
P\u00ebr shembull, nuk na nevojitet nj\u00eb ruter i v\u00ebrtet\u00eb: t\u00eb gjith\u00eb peer-t jan\u00eb n\u00eb nj\u00eb 'LAN virtuale', e lidhur me nj\u00eb instanc\u00eb specifike t\u00eb baz\u00ebs s\u00eb t\u00eb dh\u00ebnave Firebase.<\/p>\n
Prandaj, nuk na duhen adresa IP unike: p\u00ebr identifikimin unik t\u00eb peer-eve mjafton t\u00eb p\u00ebrdoren vlera unike \u00e7elash Firebase (si emrat e domain-eve), dhe \u00e7do peer cakton lokalisht adresa IP \"fiktive\" p\u00ebr \u00e7do \u00e7el\u00ebs q\u00eb duhet t\u00eb konvertohet. Kjo na liron plot\u00ebsisht nga nevoja p\u00ebr caktimin global t\u00eb adresave IP, q\u00eb \u00ebsht\u00eb nj\u00eb detyr\u00eb e nd\u00ebrlikuar.<\/p>\n
Ja minimalja API 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 e thjesht\u00eb dhe e ngjashme me API-n\u00eb Posix Sockets, por ka disa karakteristika t\u00eb r\u00ebnd\u00ebsishme: regjistrimi i thirrjeve t\u00eb prapme, caktimi i IP-ve lokale dhe lidhja \"lenive\"<\/strong>.<\/p>\nRegjistrimi i thirrjeve t\u00eb prapme<\/h2>\n \nMadje edhe n\u00ebse programi fillestar p\u00ebrdor hyrje-dalje jo bllokuese, p\u00ebr ta ekzekutuar n\u00eb nj\u00eb shfletues interneti, 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 mund t\u00eb shkruajm\u00eb kodin n\u00eb k\u00ebt\u00eb m\u00ebnyr\u00eb<\/p>\n
while(running) {\n select(...); \/\/ prit p\u00ebr ngjarje I\/O\n while(true) {\n int r = readfrom(...); \/\/ provo t\u00eb lexosh\n if (r < 0 && errno == EWOULDBLOCK) \/\/ s\u2019ka 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 p\u00ebr ne, at\u00ebher\u00eb duhet ta shnd\u00ebrrojm\u00eb n\u00eb di\u00e7ka t\u00eb ngjashme:<\/p>\n
auto cb = []() { \/\/ kjo do t\u00eb th\u00ebrritet kur jan\u00eb t\u00eb dh\u00ebna t\u00eb reja n\u00eb dispozicion\n while(true) {\n int r = readfrom(...); \/\/ p\u00ebrpiquni 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); \/\/ regjistrojini thirrjen e prapambetjes<\/code><\/pre>\n<\/p>\n
Caktoni IP lokale<\/h2>\n \nIdentifikuesit e nyjave n\u00eb 'rrjetin' ton\u00eb nuk jan\u00eb adresa IP, por \u00e7el\u00ebsa Firebase (k\u00ebto jan\u00eb vargje q\u00eb duken si: -LmEC50PYZLCiCP-vqde<\/code> ).<\/p>\nKjo \u00ebsht\u00eb e p\u00ebrshtatshme, sepse nuk kemi nevoj\u00eb p\u00ebr nj\u00eb mekaniz\u00ebm p\u00ebr caktimin e IP-ve dhe kontrollimin e unik\u00ebsis\u00eb s\u00eb tyre (si dhe t\u00eb heqim ato pas \u00e7aktivizimit t\u00eb klientit), por shpesh \u00ebsht\u00eb e nevojshme t\u00eb identifikoni peers me nj\u00eb vler\u00eb numerike.<\/p>\n
Pik\u00ebrisht p\u00ebr k\u00ebt\u00eb p\u00ebrdoren funksionet resolve<\/code> dhe reverseResolve<\/code>: aplikacioni n\u00eb nj\u00ebfar\u00eb m\u00ebnyre merr vler\u00ebn e vargut 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-s\u00eb gjithashtu p\u00ebr thjesht\u00ebsi merr k\u00ebt\u00eb vler\u00eb n\u00eb vend t\u00eb vargut.<\/p>\nKjo \u00ebsht\u00eb si nj\u00eb k\u00ebrkes\u00eb DNS, vet\u00ebm se realizohet lokalisht tek klienti.<\/p>\n
Pra, 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, duhet ta gjeneroni ndryshe.<\/p>\n
Lidhje e len\u00eb<\/h2>\n \nUDP nuk k\u00ebrkon lidhje, por, si\u00e7 e pam\u00eb, p\u00ebrpara se t\u00eb fillojm\u00eb transferimin e t\u00eb dh\u00ebnave midis dy pirat, 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 abstraksioni, (sendto<\/code>\/recvfrom<\/code> me pira t\u00eb rast\u00ebsishme pa lidhje paraprake), at\u00ebher\u00eb duhet t\u00eb kryejm\u00eb lidhje \"t\u00eb ngadalshme\" (t\u00eb vonuar) brenda API-s\u00eb.<\/p>\nK\u00ebtu \u00ebsht\u00eb se \u00e7far\u00eb ndodh gjat\u00eb shk\u00ebmbimit t\u00eb zakonsh\u00ebm t\u00eb t\u00eb dh\u00ebnave midis \"serverit\" dhe \"klientit\" kur p\u00ebrdoret UDP, dhe \u00e7far\u00eb duhet t\u00eb b\u00ebj\u00eb biblioteka jon\u00eb:<\/p>\n
\nServeri th\u00ebrret bind()<\/code>, p\u00ebr t'i njoftuar sistemit operativ q\u00eb d\u00ebshiron t\u00eb marr paketa n\u00eb portin e caktuar.<\/li>\n<\/ul>\n\nN\u00eb vend t\u00eb k\u00ebsaj, 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\u00ebnstruktur\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 vet, dhe ne shtojm\u00eb n\u00eb fillim t\u00eb datagrameve WebRTC portet e origjin\u00ebs dhe atyre p\u00ebrfundimtare, p\u00ebr t\u00eb ditur se n\u00eb cil\u00ebn radh\u00eb t\u00eb drejtojm\u00eb paket\u00ebn e re kur arrin.<\/p>\n
Thirrja \u00ebsht\u00eb jo-bllokuese, prandaj n\u00ebse nuk ka paketa, ne thjesht kthejm\u00eb -1 dhe vendosim errno=EWOULDBLOCK<\/code>.<\/p>\n\nKlienti merr n\u00ebp\u00ebrmjet mjeteve t\u00eb jashtme IP-n\u00eb dhe portin e serverit dhe b\u00ebn thirrjen sendto()<\/code>. Po ashtu, k\u00ebt\u00eb realizojm\u00eb me nj\u00eb thirrje t\u00eb brendshme bind()<\/code>, prandaj e m\u00ebposhtmja recvfrom()<\/code> do t\u00eb marr\u00eb p\u00ebrgjigje pa realizimin e qart\u00eb t\u00eb bind.<\/li>\n<\/ul>\n\nN\u00eb rastin ton\u00eb, klienti n\u00eb m\u00ebnyr\u00eb t\u00eb jashtme merr nj\u00eb \u00e7el\u00ebs n\u00eb form\u00eb stringu dhe p\u00ebrdor funksionin resolve()<\/code> p\u00ebr t\u00eb marr\u00eb IP-n\u00eb.<\/p>\nN\u00eb k\u00ebt\u00eb faz\u00eb, fillojm\u00eb \"dor\u00ebzimin\" WebRTC, n\u00ebse dy peer-a ende nuk jan\u00eb lidhur me nj\u00ebri-tjetrin. Lidhjet n\u00eb porte t\u00eb ndryshme t\u00eb nj\u00eb peer-i p\u00ebrdorin t\u00eb nj\u00ebjtin DataChannel WebRTC.<\/p>\n
Po ashtu, ne realizojm\u00eb nj\u00eb lidhje t\u00eb dyt\u00eb bind()<\/code>, n\u00eb m\u00ebnyr\u00eb q\u00eb serveri t\u00eb mund t\u00eb rikthej\u00eb lidhjen n\u00eb sendto()<\/code> rast se ajo \u00ebsht\u00eb mbyllur p\u00ebr arsye t\u00eb caktuara.<\/p>\nServeri njoftohet p\u00ebr lidhjen e klientit, kur klienti regjistron ofert\u00ebn e tij SDP n\u00eb informacionin e portit t\u00eb serverit n\u00eb Firebase, dhe serveri i p\u00ebrgjigjet atje po ashtu.<\/p>\n
\nN\u00eb diagramin e m\u00ebposht\u00ebm ilustrohet shembulli i l\u00ebvizjes s\u00eb mesazheve p\u00ebr skem\u00ebn e soketeve dhe d\u00ebrgimin e mesazhit t\u00eb par\u00eb nga klienti te serveri:<\/p>\n
Skema e plot\u00eb e faz\u00ebs s\u00eb lidhjes nd\u00ebrmjet klientit dhe serverit<\/i><\/p>\nP\u00ebrfundimi<\/h1>\n
\nN\u00ebse e keni lexuar deri n\u00eb fund, ndoshta ju intereson t\u00eb shihni teorin\u00eb n\u00eb veprim. Mund t\u00eb luani n\u00eb teeworlds.leaningtech.com<\/a><\/noindex>, provoni!<\/p>\n