Mantém e manipula requisições relacionadas ao ViewState

ViewStateSessionHandler.js

/**
 * Depends on
 * https://gist.github.com/w35l3y/1d4e5578f7ce9d2a3d434729585defa6/
 * https://github.com/w35l3y/userscripts/raw/master-greasemonkey/includes/Includes_HttpRequest/
 */

function Session (errorFn) {
  logger.info("Sessão iniciada.");

  var dvs = document.querySelector("input[name = 'javax.faces.ViewState']");
  if (!dvs) {
    throw "ViewState não encontrado ao requisitar página principal";
  }

  var _this = this;
  var actions = function (m, action, resolve, reject) {
    var a = (action && "#" != action?(/^https?:/.test(action)?"":location.origin) + action:location.href);

    logger.info("%s %s", m, a);

    return {
      method: m,
      url: a,
      onsuccess: function (xhr) {
        var xml = xhr.response.xml;
        logger.info("Document", xml);

        var inputViewState = xml.querySelector("#javax\\.faces\\.ViewState,input[name = 'javax.faces.ViewState']");
        logger.info("Input ViewState", inputViewState);
        var errors = errorFn(xml);
        if (inputViewState) {
          _this.viewState = inputViewState.value || inputViewState.textContent;
          logger.info("ViewState", _this.viewState);
        } else {
          logger.error("Erro", errors, [m, action], a, xml, xhr.response.raw);
          reject(xml, _this);
          return
        }

        if (0 < errors.length) {
          logger.error("Erro", errors, [m, action], a, xml, xhr.response.raw);
          reject(xml, _this);
        } else {
          logger.info("Página retornada");
          resolve(xml, _this);
        }
      },
      onfail: function () {
        logger.info("Fail", arguments);
        reject(xhr.response.xml, _this);
      }
    };
  };

  this.clone = function () {
    var ses = new Session(errorFn);
    ses.viewState = _this.viewState;

    return ses;
  };
  
  this.viewState = dvs.value;

  this.update = function (doc) {
    logger.warn("Atualizando ViewState do documento...", doc);

    doc.querySelectorAll("#javax\\.faces\\.ViewState,input[name = 'javax.faces.ViewState']").forEach(function (vs) {
      vs.value = _this.viewState;
    });
  };
  
  this.submit = function (action, sync, event) {
    if (!action) {
      logger.info("Ação não encontrada na página.");
      return Promise.reject(null, _this);
    }

    var d = action.ownerDocument;
    logger.info("Ação identificada.", action);
    logger.info("Verificando documento da ação informada...", d === document);
    if (d === document) { // current page
      logger.info("Verificando sincronicidade do evento...");
      if (sync) {
        action.click();
        logger.info("Evento CLICK executado com sucesso.");;
        return Promise.resolve(d, _this);
      }
    }
    _this.update(d);

    var form = action.form;
    var params = [];
    var partialUpdate = false;
    logger.info("Verificando tipo de ação assincrona...");
    if (action instanceof HTMLAnchorElement && "#" == action.getAttribute("href") && /'([^']+)'\),{'([^']+)'/.test(action.getAttribute("onclick") || action.getAttribute("data-onclick"))) {
      form = d.getElementById(RegExp.$1);
      action = d.createElement("input");

      action.setAttribute("name", RegExp.$2);
      action.setAttribute("value", RegExp.$2);

      logger.info("Criada ação FAKE para simular o envio de formulário...", action, RegExp.$1, RegExp.$2);
    } else if (action instanceof HTMLAnchorElement && /^#((\w+):\w+)/.test(action.getAttribute("href"))) {
      if (!event) {
        logger.error("Ausência de evento reconhecido...", action);
        return Promise.reject(d);
      }
      var containerId = RegExp.$2;
      logger.info("Container...", containerId)
      var container = d.getElementById(containerId);
      form = container.querySelector("form");
      
      params.push({name:"javax.faces.partial.execute", value: containerId});
      params.push({name:"javax.faces.partial.render", value: containerId});
      params.push({name:"javax.faces.source", value: containerId});
      params.push({name:"javax.faces.partial.event", value: event});
      params.push({name:"javax.faces.behavior.event", value: event});
      if ("tabChange" == event) {
        params.push({name:containerId + "_contentLoad", value: "true"});
        params.push({name:containerId + "_newTab", value: RegExp.$1});
        params.push({name:containerId + "_tabindex", value: xpath("./ancestor::ul[1]/li", action).reduce(function (s, v, i) {return null !== s?s:(v == action.parentNode?i:null)}, null)});
      }

      partialUpdate = {
        id       : containerId,
        event    : event,
        action   : action,
        container: d.querySelector("#" + escapeRegex(RegExp.$1))
      };

      action = d.createElement("input");
      
      action.setAttribute("name", "javax.faces.partial.ajax");
      action.setAttribute("value", "true");
    } else if (event) {
      logger.error("Evento em ACTION não reconhecida.", action, event);
      return Promise.reject(d);
    }
    
    logger.info("Parâmetros adicionais à requisição...", params);
    if (form instanceof HTMLFormElement) {
      logger.info("Enviando formulário...", form);
      return new Promise(function (resolve, reject) {
        var fields = Array.prototype.slice.apply(form.elements).filter(function (field) {
          return !(field instanceof HTMLButtonElement) && !(field instanceof HTMLFieldSetElement);
        });
        Array.prototype.push.apply(fields, params);
        logger.info("Verificando existência de campo...");
        if (-1 == fields.indexOf(action)) {
          logger.info("Campo adicionado.", action);
          fields.push(action);
        }

        var openData = actions(form.method.toUpperCase(), form.action, function (xml) {
          if (!partialUpdate) {
            return resolve(xml);
          }

          var viewStateTmp = null;
          xpath(".//changes/update[@id]", xml).forEach(function (update) {
            var id = update.getAttribute("id");
            logger.warn("Atualização parcial...", id, update);

            switch (id) {
              case "javax.faces.ViewState": // Altera value do campo
                Array.prototype.slice.apply(d.querySelectorAll("#javax\\.faces\\.ViewState,input[name = 'javax.faces.ViewState']")).forEach(function (element) {
                  logger.warn("Atualizando ViewState...", element, update);
                  viewStateTmp = update.textContent;
                  element.value = update.textContent;
                  element.setAttribute("value", update.textContent);
                });
                break;
              case partialUpdate.container.id: // Altera o container
                logger.warn("Sobreescrevendo container...", d, partialUpdate, update);
                d.getElementById(partialUpdate.id).innerHTML = update.textContent;
                break;
              default: // Sobreescreve o elemento
                Array.prototype.slice.apply(d.querySelectorAll("#" + escapeRegex(update.getAttribute("id")))).forEach(function (element) {
                  logger.warn("Sobreescrevendo elemento...", element, update);
                  element.outerHTML = update.textContent;
                });
                break;
            }
          });

          var inputViewState = document.createElement("input");
          inputViewState.setAttribute("id", "javax.faces.ViewState");
          inputViewState.setAttribute("name", "javax.faces.ViewState");
          inputViewState.setAttribute("autocomplete", "off");
          inputViewState.setAttribute("type", "hidden");

          // @TODO Verificar se estas linhas são mesmo necessárias ou se basta incluir o input vazio já que o update é feito antes das requisições
          inputViewState.value = viewStateTmp;
          inputViewState.setAttribute("value", viewStateTmp);

          logger.warn("Inserindo ViewState nos forms do container...", inputViewState);
          xpath("form", d.getElementById(partialUpdate.id)).forEach(function (f) {
            logger.warn("ViewState inserido...", f);
            f.insertBefore(inputViewState.cloneNode(true), f.firstElementChild);
          });

          executePartialAction(partialUpdate);

          resolve(d);
        }, reject);
        logger.info("Informações do formulário a serem enviadas...", fields, form, resolve);
        logger.warn("Requisição FORM...", openData, fields);
        HttpRequest.open(openData).send(fields);
      });
    }
    
    logger.info("Acessando link...", action);
    return new Promise(function (resolve, reject) {
      var openData = actions("GET", action.getAttribute("href"), resolve, reject);
      var sendData = params.reduce(function (s, v) {
        s[v.name] = v.value;
        return s;
      }, {});
      logger.warn("Requisição LINK...", openData, sendData);
      HttpRequest.open(openData).send(sendData);
    });
  }
}