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In CasperJS, add a cookie through the underlying PhantomJS page object: this.page.addCookie({...}). Call it while the page is on a URL whose domain matches the cookie, check the Boolean result, and then reload or continue to the action that needs the cookie. The method supports attributes such as path, secure, httponly, and expires.
The direct CasperJS solution
CasperJS exposes its PhantomJS WebPage instance as this.page. PhantomJS documents page.addCookie(cookie) as the supported way to set a cookie, and the method returns true when the cookie is accepted or false when it is rejected.
var casper = require('casper').create();
var target = 'https://example.com/';
casper.start(target, function () {
var added = this.page.addCookie({
name: 'session',
value: 'abc123',
domain: 'example.com',
path: '/',
secure: true,
httponly: true
});
this.echo('Cookie added: ' + added);
});
// Open the URL again so the next request is made with the new cookie.
casper.thenOpen(target, function () {
this.echo('Page opened after setting the cookie.');
});
casper.run();Replace the host, cookie name, value, and attributes with the values required by the site. The domain must match the current page; a mismatch can cause PhantomJS to reject or ignore the cookie. The example first opens the target, sets the cookie, and opens the target again so a subsequent request can use it.
CasperJS’s project repository describes CasperJS as a navigation utility for PhantomJS and exposes the page object used above. See the CasperJS project and PhantomJS’s addCookie documentation.
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How the cookie-setting sequence works
1. Create a CasperJS instance
Start with require('casper').create(). CasperJS callbacks run with the Casper instance as this, which is why the WebPage object is available as this.page.
2. Navigate to a matching host
Use casper.start() with the target URL. Adding a cookie while the page is associated with the target host avoids the domain-mismatch failure documented by PhantomJS. A cookie for example.com should not be added while the current page belongs to an unrelated host.
3. Add the cookie and capture the result
Pass an object to this.page.addCookie() and save its return value. Do not assume that the call succeeded merely because the script continued running.
4. Make the request that needs the cookie
If the cookie must be sent as an HTTP request cookie, open or reload the target after adding it. For a page-only cookie that is read by the current document, you can perform the page action in the same navigation callback, but reopening the URL is the clearer pattern for authentication or server-side state.
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5. Verify the result on the target URL
PhantomJS exposes page.cookies, an array of cookies visible to the current URL. Inspect that property after setting the cookie and on the page where you expect it to be available.
casper.start('https://example.com/', function () {
var added = this.page.addCookie({
name: 'theme',
value: 'dark',
domain: 'example.com',
path: '/'
});
this.echo('addCookie returned: ' + added);
var visible = this.page.cookies;
this.echo('Visible cookie count: ' + visible.length);
for (var i = 0; i < visible.length; i++) {
this.echo(visible[i].name + '=' + visible[i].value);
}
});
casper.run();page.cookies reports cookies visible to the current URL, not an unrestricted browser-wide store. Check it after navigation to the host and path you care about.
Cookie object fields to choose deliberately
PhantomJS documents a cookie object with a required name and value plus attributes that control where and how it applies. Use only the attributes needed by the target site.
| Field | What to provide | Practical check |
|---|---|---|
name |
The cookie name. | Use the exact name expected by the application. |
value |
The value, such as a session or preference token. | Copy the value exactly; do not add surrounding quotes unless the site requires them. |
domain |
The cookie’s host scope. | It must be appropriate to the current page. A mismatch can make addCookie return false. |
path |
The URL path scope, commonly / when the site expects the cookie throughout the host. |
Use a path that covers the request or page where you will verify the cookie. |
secure |
A Boolean indicating the secure attribute required by the target. | Use the setting expected by the site and test on the same HTTPS/HTTP scheme used in the script. |
httponly |
A Boolean for an HttpOnly cookie. | Set it through addCookie; page JavaScript cannot create an HttpOnly cookie. |
expires (also documented as expiry in the cookie property documentation) |
An expiration value when the site requires one. | Use the format accepted by the PhantomJS version installed with your CasperJS setup. |
The PhantomJS reference lists these fields and recommends page.addCookie for setting cookies. Its property reference for page.cookies describes the cookies visible to the current URL.
Setting a cookie before a page action
The phrase “before opening a page” needs care. PhantomJS checks the cookie against the page context, so trying to add a cookie for a site while the current page is unrelated can fail. A dependable CasperJS sequence is:
- Open the target host with
casper.start(). - Call
this.page.addCookie()in that navigation callback. - Check the Boolean return value.
- Use
casper.thenOpen()to request the target again, or continue with the next navigation or interaction.
This sequence sets the cookie before the request that follows it, while keeping the current page’s domain aligned with the cookie’s domain. If a site needs a cookie on a subpath, set path to a value that covers that subpath rather than assuming that every URL will see it.
HttpOnly cookies and casper.evaluate()
casper.evaluate() executes JavaScript in the remote page’s DOM context, similar to entering code in that page’s browser console. That is a different mechanism from the PhantomJS WebPage API.
Use evaluate() only for a cookie that page JavaScript is allowed to create. Page JavaScript cannot create an HttpOnly cookie. When the cookie must carry the httponly attribute, supply it in the object passed to this.page.addCookie().
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casper.start('https://example.com/', function () {
var added = this.page.addCookie({
name: 'server_session',
value: 'abc123',
domain: 'example.com',
path: '/',
secure: true,
httponly: true
});
this.echo('HttpOnly cookie accepted: ' + added);
});
casper.run();Do not use a DOM-script workaround when the requirement is an HttpOnly cookie; it cannot create that attribute.
Why CasperJS cookies are rejected or appear to do nothing
| Symptom | Likely cause | Fix |
|---|---|---|
addCookie prints false |
The cookie domain does not match the current page, or another cookie attribute is not accepted for that page. | Open the target host first, make domain match it, use a covering path, and test again while checking the Boolean result. |
The call returns true, but the next request is unauthenticated |
The page was not reopened after the cookie was added, or the cookie is scoped to a different path. | Navigate to the target again after addCookie and verify this.page.cookies on that URL. |
The cookie is missing from page.cookies |
You inspected a URL outside the cookie’s domain or path. | Inspect from the host and path covered by the cookie object. |
| A JavaScript assignment does not create the required cookie | The cookie needs the HttpOnly attribute, which page JavaScript cannot set. | Use this.page.addCookie() with httponly: true. |
| A secure-cookie flow behaves differently between environments | The secure attribute and the URL scheme do not match the target’s expectations. |
Run against the same HTTPS or HTTP endpoint used by the real flow and set the documented attribute explicitly. |
| The script works on one site but not another | Cookie policy, redirects, hostnames, paths, or authentication flows differ by site. | Log the URL being opened, check the cookie’s domain and path, inspect the Boolean return, and verify visibility after each redirect. |
A successful API call is not proof that the target application will authenticate the session. The application may require additional cookies, a particular path, a redirect sequence, or values generated by its own login flow. Validate the result on the actual page and request that consume the cookie.
Checking your CasperJS and PhantomJS versions
This technique belongs to a legacy stack. The official CasperJS repository states, “CasperJS is no longer actively maintained.” Its documentation is labeled 1.1.0-DEV, and PhantomJS’s cookie API is likewise a legacy WebPage interface. Confirm which CasperJS and PhantomJS binaries your script is actually using, then test the cookie flow against the target site rather than assuming modern-browser compatibility.
Neither the CasperJS project page nor the PhantomJS cookie references guarantee that a particular authentication flow, bot check, consent system, or modern web application will work in this environment. If the target depends on browser capabilities that PhantomJS does not provide, changing the cookie object alone will not resolve the incompatibility. See the CasperJS repository for the project’s maintenance status and documentation links.
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)
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FAQ
Will this make CasperJS compatible with every modern website?
No. CasperJS is no longer actively maintained, and PhantomJS is a legacy browser engine. A correctly scoped cookie can still fail when the site requires browser features or an authentication sequence that this stack does not support.
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No. page.cookies is the readable collection of cookies visible to the current URL. PhantomJS documents page.addCookie as the setting operation.
Frequently Asked Questions
Will this make CasperJS compatible with every modern website?
No. CasperJS is no longer actively maintained, and PhantomJS is a legacy browser engine. A correctly scoped cookie can still fail when the site requires browser features or an authentication sequence that this stack does not support.
Can I use page.cookies instead of addCookie to set a cookie?
No. page.cookies is the readable collection of cookies visible to the current URL. PhantomJS documents page.addCookie as the setting operation.
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