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Exchange Web Service - query problems

Exista mai multe versiuni de Exchange Server, majoritatea serverelor care exista la ora actuala sunt 2007 SP1 si 2010. Daca vrem sa scriem o aplicatie care acceseze direct contul de Exchange puteti sa folosim un client care consuma serviciile expuse de acest server precum EWS - Exchange Web Service. Aceasta este doar un assembly pe care trebuie sa il adaugam la proiect. Pregatesc in aceasta luna mai multe tutoriale despre EWS. In postul de azi vreau doar sa subliniez o problema pe care EWS o are. O sa vorbim mai in detaliu cu alta ocazie despre cum sa il folosim.
Exchange Server 2010 a adus cateva schimbari la nivelul entitatiilor care exista. De exemplu pe 2010 un contact poate sa aibe atasata o poza sau modul in care sunt grupate contactele difera fata de 2007. Din pacate EWS ne aduce datele in functie de versiune de Exchange pe care o accesam.
Un exemplu destul de bun, pentru a arata problema care o are EWS este cand vrem sa aducem lista de contactele a unui account. O sa ne trezim ca versiunea 2007 SP1 ne aduce obiecte de tip ExpandGroupResult, pe cand 2010 ne aduce obiecte de tip GroupMember.
Aceste probleme ma sperie, nu neaparat ca trebuie sa scriu un IF in plus, nu ar fi nici o problema, dar ce o sa ne facem cand apara urmatoarea versiunea de Exchange? Cand o sa dorim sa ne conectam la Exchange Server 20xx o sa ne trezim ca aplicatia crapa, deoarece rezultatele pe care il primim difera. Notiunea de backward compatible nu exista in acest caz si nici notiunea ca o metoda ar trebuii sa returneze un singur tip de data sau macar datele returnate sa aibe o interfata comuna, daca nu un base class.
Principala problema asa cum o vad eu vine de la libraria EWS. Chiar daca ea primeste de la server date de tipuri diferite, ar trebuii sa expuna consumatorului date de aceleasi tip.
Nu stiu ce schimbari o sa aduca urmatoarea versiune de Exchange, dar mentenanta pe aplicatiile care folosesc EWS nu o sa fie tocmai atat de placuta.

Comments

  1. Oare si ActiveSync are aceleasi probleme de backward compatibility?

    Am banuiala ca Exchange (ca si Lotus Domino), nu prea au fost gandite de la bun inceput sa fie folosite in mod curent de aplicatii externe third-party, ci mai degraba s-au focusat pe development-ul de aplicatii bazate pe clientii proprii, gen Outlook sau Lotus Notes.. (gen formuri cu VBScript respectiv LotusScript in spate..)

    ReplyDelete
  2. Cand faci public o librarie care este mapata peste propriile tale servicii, ma astept sa fie consistenta sau macar documentata.

    ReplyDelete
  3. Adevarat, asa ar trebui sa fie.. Din pacate, cu cat un API/web service e folosit de mai putine persoane, cu atat unii autori se simt mai putin motivati sa mentina backward/forward compatibility..

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