How to submit a form using PhantomJS

Question

I'm trying to use phantomJS (what an awesome tool btw!) to submit a form for a page that I have login credentials for, and then output the content of the destination page to stdout. I'm able to access the form and set its values successfully using phantom, but I'm not quite sure what the right syntax is to submit the form and output the content of the subsequent page. What I have so far is:

var page = new WebPage();
var url = phantom.args[0];

page.open(url, function (status) {

  if (status !== 'success') {
      console.log('Unable to access network');
  } else {

    console.log(page.evaluate(function () {

      var arr = document.getElementsByClassName("login-form");
      var i;

      for (i=0; i < arr.length; i++) {

        if (arr[i].getAttribute('method') == "POST") {
          arr[i].elements["email"].value="[email protected]";
          arr[i].elements["password"].value="mypassword";

          // This part doesn't seem to work. It returns the content
          // of the current page, not the content of the page after
          // the submit has been executed. Am I correctly instrumenting
          // the submit in Phantom?
          arr[i].submit();
          return document.querySelectorAll('html')[0].outerHTML;
        }

      }

      return "failed :-(";

    }));
  }

  phantom.exit();
}

Answer 1

I figured it out. Basically it's an async issue. You can't just submit and expect to render the subsequent page immediately. You have to wait until the onLoad event for the next page is triggered. My code is below:

var page = new WebPage(), testindex = 0, loadInProgress = false;

page.onConsoleMessage = function(msg) {
  console.log(msg);
};

page.onLoadStarted = function() {
  loadInProgress = true;
  console.log("load started");
};

page.onLoadFinished = function() {
  loadInProgress = false;
  console.log("load finished");
};

var steps = [
  function() {
    //Load Login Page
    page.open("https://website.example/theformpage/");
  },
  function() {
    //Enter Credentials
    page.evaluate(function() {

      var arr = document.getElementsByClassName("login-form");
      var i;

      for (i=0; i < arr.length; i++) {
        if (arr[i].getAttribute('method') == "POST") {

          arr[i].elements["email"].value="mylogin";
          arr[i].elements["password"].value="mypassword";
          return;
        }
      }
    });
  },
  function() {
    //Login
    page.evaluate(function() {
      var arr = document.getElementsByClassName("login-form");
      var i;

      for (i=0; i < arr.length; i++) {
        if (arr[i].getAttribute('method') == "POST") {
          arr[i].submit();
          return;
        }
      }

    });
  },
  function() {
    // Output content of page to stdout after form has been submitted
    page.evaluate(function() {
      console.log(document.querySelectorAll('html')[0].outerHTML);
    });
  }
];

interval = setInterval(function() {
  if (!loadInProgress && typeof steps[testindex] == "function") {
    console.log("step " + (testindex + 1));
    steps[testindex]();
    testindex++;
  }
  if (typeof steps[testindex] != "function") {
    console.log("test complete!");
    phantom.exit();
  }
}, 50);

Answer 2

Also, CasperJS provides a nice high-level interface for navigation in PhantomJS, including clicking on links and filling out forms.

CasperJS

Updated to add July 28, 2015 article comparing PhantomJS and CasperJS.

(Thanks to commenter Mr. M!)