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BrowserUp Proxy is a free utility to watch, test, and manipulate web application network traffic and performance.
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README.md

BrowserUp Proxy

The BrowserUp Proxy allows you to manipulate HTTP requests and responses, capture HTTP content, and export performance data as a HAR file. BrowserUp Proxy works well as a standalone proxy server, but it is especially useful when embedded in Selenium tests.

BrowserUp Proxy is originally forked from BrowserMobProxy and is powered by LittleProxy. See [CHANGELOG.md] for updates.

If you're running BrowserUp Proxy within a Java application or Selenium test, get started with Embedded Mode. If you want to run BUP from the command line as a standalone proxy, start with Standalone.

Getting started: Embedded Mode

To use BrowserUp Proxy in your tests or application, add the browserup-proxy-core dependency to your pom:

    <dependency>
        <groupId>com.browserup</groupId>
        <artifactId>browserup-proxy-core</artifactId>
        <version>1.0.0</version>
        <scope>test</scope>
    </dependency>

Start the proxy:

    BrowserUpProxy proxy = new BrowserUpProxyServer();
    proxy.start();
    int port = proxy.getPort(); // get the JVM-assigned port
    // Selenium or HTTP client configuration goes here

Then configure your HTTP client to use a proxy running at the specified port.

Using with Selenium? See the Using with Selenium section.

Getting started: Standalone

To run in standalone mode from the command line, first download the latest release from the releases page, or build the latest from source.

Start the REST API:

    ./browserup-proxy -port 8080

Then create a proxy server instance:

    curl -X POST http://localhost:8080/proxy
    {"port":8081}

The "port" is the port of the newly-created proxy instance, so configure your HTTP client or web browser to use a proxy on the returned port. For more information on the features available in the REST API, see the REST API documentation.

Features and Usage

The proxy is programmatically controlled via a REST interface or by being embedded directly inside Java-based programs and unit tests. It captures performance data in the HAR format. In addition it can actually control HTTP traffic, such as:

  • blacklisting and whitelisting certain URL patterns
  • simulating various bandwidth and latency
  • remapping DNS lookups
  • flushing DNS caching
  • controlling DNS and request timeouts
  • automatic BASIC authorization

REST API

To get started, first start the proxy by running browserup-proxy or browserup-proxy.bat in the bin directory:

$ sh browserup-proxy -port 8080
INFO 05/31 03:12:48 o.b.p.Main           - Starting up...
2011-05-30 20:12:49.517:INFO::jetty-7.3.0.v20110203
2011-05-30 20:12:49.689:INFO::started o.e.j.s.ServletContextHandler{/,null}
2011-05-30 20:12:49.820:INFO::Started SelectChannelConnector@0.0.0.0:8080

Once started, there won't be an actual proxy running until you create a new proxy. You can do this by POSTing to /proxy:

[~]$ curl -X POST http://localhost:8080/proxy
{"port":8081}

or optionally specify your own port:

[~]$ curl -X POST -d 'port=8089' http://localhost:8080/proxy
{"port":8089}

or if running BrowserUp Proxy in a multi-homed environment, specify a desired bind address (default is 0.0.0.0):

[~]$ curl -X POST -d 'bindAddress=192.168.1.222' http://localhost:8080/proxy
{"port":8086}

Once that is done, a new proxy will be available on the port returned. All you have to do is point a browser to that proxy on that port and you should be able to browse the internet. The following additional APIs will then be available:

Description HTTP method Request path Request parameters
Get a list of ports attached to ProxyServer instances managed by ProxyManager GET /proxy
Creates a new proxy to run requests off of POST /proxy

port - Integer, The specific port to start the proxy service on. Optional, default is generated and returned in response.

proxyUsername - String, The username to use to authenticate with the chained proxy. Optional, default to null.

proxyPassword - String, The password to use to authenticate with the chained proxy. Optional, default to null.

bindAddress - String, If running BrowserUp Proxy in a multi-homed environment, specify a desired bind address. Optional, default to "0.0.0.0".

serverBindAddress - String, If running BrowserUp Proxy in a multi-homed environment, specify a desired server bind address. Optional, default to "0.0.0.0".

useEcc - Boolean. True, Uses Elliptic Curve Cryptography for certificate impersonation. Optional, default to "false".

trustAllServers - Boolean. True, Disables verification of all upstream servers' SSL certificates. All upstream servers will be trusted, even if they do not present valid certificates signed by certification authorities in the JDK's trust store. Optional, default to "false".

Creates a new HAR attached to the proxy and returns the HAR content if there was a previous HAR. [port] in request path it is port where your proxy was started PUT /proxy/[port]/har

captureHeaders - Boolean, capture headers or not. Optional, default to "false".

captureCookies - Boolean, capture cookies or not. Optional, default to "false".

captureContent - Boolean, capture content bodies or not. Optional, default to "false".

captureBinaryContent - Boolean, capture binary content or not. Optional, default to "false".

initialPageRef - The string name of The first page ref that should be used in the HAR. Optional, default to "Page 1".

initialPageTitle - The title of first HAR page. Optional, default to initialPageRef.

Starts a new page on the existing HAR. [port] in request path it is port where your proxy was started PUT /proxy/[port]/har/pageRef

pageRef - The string name of the first page ref that should be used in the HAR. Optional, default to "Page N" where N is the next page number.

pageTitle - The title of new HAR page. Optional, default to pageRef.

Shuts down the proxy and closes the port. [port] in request path it is port where your proxy was started DELETE /proxy/[port]
Returns the JSON/HAR content representing all the HTTP traffic passed through the proxy (provided you have already created the HAR with this method) GET /proxy/[port]/har
Displays whitelisted items GET /proxy/[port]/whitelist
Sets a list of URL patterns to whitelist PUT /proxy/[port]/whitelist

regex - A comma separated list of regular expressions.

status - The HTTP status code to return for URLs that do not match the whitelist.

Clears all URL patterns from the whitelist DELETE /proxy/[port]/whitelist
Displays blacklisted items GET /proxy/[port]/blacklist
Set a URL to blacklist PUT /proxy/[port]/blacklist

regex - The blacklist regular expression.

status - The HTTP status code to return for URLs that are blacklisted.

method - The regular expression for matching HTTP method (GET, POST, PUT, etc). Optional, by default processing all HTTP method.

Clears all URL patterns from the blacklist DELETE /proxy/[port]/blacklist
Limit the bandwidth through the proxy on the [port] PUT /proxy/[port]/limit

downstreamKbps - Sets the downstream bandwidth limit in kbps. Optional.

upstreamKbps - Sets the upstream bandwidth limit kbps. Optional, by default unlimited.

downstreamMaxKB - Specifies how many kilobytes in total the client is allowed to download through the proxy. Optional, by default unlimited.

upstreamMaxKB - Specifies how many kilobytes in total the client is allowed to upload through the proxy. Optional, by default unlimited.

latency - Add the given latency to each HTTP request. Optional, by default all requests are invoked without latency.

enable - A boolean that enable bandwidth limiter. Optional, by default to "false", but setting any of the properties above will implicitly enable throttling

payloadPercentage - Specifying what percentage of data sent is payload, e.g. use this to take into account overhead due to tcp/ip. Optional.

maxBitsPerSecond - The max bits per seconds you want this instance of StreamManager to respect. Optional.

Displays the amount of data remaining to be uploaded/downloaded until the limit is reached GET /proxy/[port]/limit
Set and override HTTP Request headers POST /proxy/[port]/headers Payload data should be JSON encoded set of headers. Where key is a header name (such as "User-Agent") and value is a value of HTTP header to setup (such as "BrowserUp-Agent"). Example: {"User-Agent": "BrowserUp-Agent"}
Overrides normal DNS lookups and remaps the given hosts with the associated IP address POST /proxy/[port]/hosts Payload data should be JSON encoded set of hosts. Where key is a host name (such as "example.com") and value is a IP address which associatied with host hame (such as "1.2.3.4"'). Example: {"example.com": "1.2.3.4"}
Sets automatic basic authentication for the specified domain POST /proxy/[port]/auth/basic/[domain] Payload data should be JSON encoded username and password name/value pairs. Example: {"username": "myUsername", "password": "myPassword"}
Wait till all request are being made PUT /proxy/[port]/wait

quietPeriodInMs - Wait till all request are being made. Optional.

timeoutInMs - Sets quiet period in milliseconds. Optional.

Handles different proxy timeouts PUT proxy/[port]/timeout

Payload data should be JSON encoded set of parameters. Where key is a parameters name (such as "connectionTimeout") and value is a value of parameter to setup (such as "500")

requestTimeout - Request timeout in milliseconds. A timeout value of -1 is interpreted as infinite timeout. Optional, default to "-1".

readTimeout - Read timeout in milliseconds. Which is the timeout for waiting for data or, put differently, a maximum period inactivity between two consecutive data packets). A timeout value of zero is interpreted as an infinite timeout. Optional, default to "60000".

connectionTimeout - Determines the timeout in milliseconds until a connection is established. A timeout value of zero is interpreted as an infinite timeout. Optional, default to "60000".

dnsCacheTimeout - Sets the maximum length of time that records will be stored in this Cache. A nonpositive value disables this feature (that is, sets no limit). Optional, default to "0".

Example: {"connectionTimeout" : "500", "readTimeout" : "200"}
Redirecting URL's PUT /proxy/[port]/rewrite

matchRegex - A matching URL regular expression.

replace - replacement URL.

Removes all URL redirection rules currently in effect DELETE /proxy/[port]/rewrite
Setting the retry count PUT /proxy/[port]/retry

retrycount - The number of times a method will be retried.

Empties the DNS cache DELETE /proxy/[port]/dns/cache
REST API interceptors with LittleProxy
Describe your own request interception POST /proxy/[port]/filter/request A string which determinates interceptor rules. See more here
Describe your own response interception POST /proxy/[port]/filter/response A string which determinates interceptor rules. See more here
Describe your own request interception POST /proxy/[port]/interceptor/request A string which determinates interceptor rules. See more here
Describe your own response interception POST /proxy/[port]/interceptor/response A string which determinates interceptor rules. See more here

For example, once you've started the proxy you can create a new HAR to start recording data like so:

[~]$ curl -X PUT -d 'initialPageRef=Foo' http://localhost:8080/proxy/8081/har

Now when traffic goes through port 9091 it will be attached to a page reference named "Foo". Consult the HAR specification for more info on what a "pageRef" is. You can also start a new pageRef like so:

[~]$ curl -X PUT -d 'pageRef=Bar' http://localhost:8080/proxy/8081/har/pageRef

That will ensure no more HTTP requests get attached to the old pageRef (Foo) and start getting attached to the new pageRef (Bar). After creating the HAR, you can get its content at any time like so:

[~]$ curl http://localhost:8080/proxy/8081/har

Sometimes you will want to route requests through an upstream proxy server. In this case specify your proxy server by adding the httpProxy parameter to your create proxy request:

[~]$ curl -X POST http://localhost:8080/proxy?httpProxy=yourproxyserver.com:8080
{"port":8081}

Alternatively, you can specify the upstream proxy config for all proxies created using the standard JVM system properties for HTTP proxies. Note that you can still override the default upstream proxy via the POST payload, but if you omit the payload the JVM system properties will be used to specify the upstream proxy.

Command-line Arguments

  • -port <port>
  • Port on which the API listens. Default value is 8080.
  • -address
  • Address to which the API is bound. Default value is 0.0.0.0.
  • -proxyPortRange <from>-<to>
  • Range of ports reserved for proxies. Only applies if port parameter is not supplied in the POST request. Default values are <port>+1 to <port>+500+1.
  • -ttl <seconds>
  • Proxy will be automatically deleted after a specified time period. Off by default.

Embedded Mode

BrowserUp Proxy separates the Embedded Mode and REST API into two modules. If you only need Embedded Mode functionality, add the browserup-core artifact as a dependency. The REST API artifact is browserup-rest.

If you're using Java and Selenium, the easiest way to get started is to embed the project directly in your test. First, you'll need to make sure that all the dependencies are imported in to the project. You can find them in the lib directory. Or, if you're using Maven, you can add this to your pom:

    <dependency>
        <groupId>com.browserup</groupId>
        <artifactId>browserup-proxy-core</artifactId>
        <version>1.0.0/version>
        <scope>test</scope>
    </dependency>

Once done, you can start a proxy using com.browserup.bup.BrowserUpProxy:

    BrowserUpProxy proxy = new BrowserUpProxyServer();
    proxy.start();
    // get the JVM-assigned port and get to work!
    int port = proxy.getPort();
    //...

Consult the Javadocs on the com.browserup.bup.BrowserUpProxy class for the full API.

Using With Selenium

Selenium 3 users: Due to a geckodriver issue, Firefox 51 and lower do not properly support proxies with WebDriver's DesiredCapabilities. See this answer for a suitable work-around.

BrowserUp Proxy makes it easy to use a proxy in Selenium tests:

    // start the proxy
    BrowserUpProxy proxy = new BrowserUpProxyServer();
    proxy.start();

    // get the Selenium proxy object
    Proxy seleniumProxy = ClientUtil.createSeleniumProxy(proxy);

    // configure it as a desired capability
    DesiredCapabilities capabilities = new DesiredCapabilities();
    capabilities.setCapability(CapabilityType.PROXY, seleniumProxy);

    // start the browser up
    WebDriver driver = new FirefoxDriver(capabilities);

    // enable more detailed HAR capture, if desired (see CaptureType for the complete list)
    proxy.enableHarCaptureTypes(CaptureType.REQUEST_CONTENT, CaptureType.RESPONSE_CONTENT);

    // create a new HAR with the label "yahoo.com"
    proxy.newHar("yahoo.com");

    // open yahoo.com
    driver.get("http://yahoo.com");

    // get the HAR data
    Har har = proxy.getHar();

Note: If you're running running tests on a Selenium grid, you will need to customize the Selenium Proxy object created by createSeleniumProxy() to point to the hostname of the machine that your test is running on. You can also run a standalone BrowserUp Proxy instance on a separate machine and configure the Selenium Proxy object to use that proxy.

(LittleProxy) interceptors

There are four methods to support request and response interception in LittleProxy:

  • addRequestFilter
  • addResponseFilter
  • addFirstHttpFilterFactory
  • addLastHttpFilterFactory

For most use cases, including inspecting and modifying requests/responses, addRequestFilter and addResponseFilter will be sufficient. The request and response filters are easy to use:

    proxy.addRequestFilter(new RequestFilter() {
            @Override
            public HttpResponse filterRequest(HttpRequest request, HttpMessageContents contents, HttpMessageInfo messageInfo) {
                if (messageInfo.getOriginalUri().endsWith("/some-endpoint-to-intercept")) {
                    // retrieve the existing message contents as a String or, for binary contents, as a byte[]
                    String messageContents = contents.getTextContents();

                    // do some manipulation of the contents
                    String newContents = messageContents.replaceAll("original-string", "my-modified-string");
                    //[...]

                    // replace the existing content by calling setTextContents() or setBinaryContents()
                    contents.setTextContents(newContents);
                }

                // in the request filter, you can return an HttpResponse object to "short-circuit" the request
                return null;
            }
        });

        // responses are equally as simple:
        proxy.addResponseFilter(new ResponseFilter() {
            @Override
            public void filterResponse(HttpResponse response, HttpMessageContents contents, HttpMessageInfo messageInfo) {
                if (/*...some filtering criteria...*/) {
                    contents.setTextContents("This message body will appear in all responses!");
                }
            }
        });

With Java 8, the syntax is more concise:

        proxy.addResponseFilter((response, contents, messageInfo) -> {
            if (/*...some filtering criteria...*/) {
                contents.setTextContents("This message body will appear in all responses!");
            }
        });

See the javadoc for the RequestFilter and ResponseFilter classes for more information.

For fine-grained control over the request and response lifecycle, you can add "filter factories" directly using addFirstHttpFilterFactory and addLastHttpFilterFactory (see the examples in the InterceptorTest unit tests).

REST API interceptors with LittleProxy

When running the REST API with LittleProxy enabled, you cannot use the legacy /:port/interceptor/ endpoints. Instead, POST the javascript payload to the new /:port/filter/request and /:port/filter/response endpoints.

Request filters

Javascript request filters have access to the variables request (type io.netty.handler.codec.http.HttpRequest), contents (type com.browserup.bup.util.HttpMessageContents), and messageInfo (type com.browserup.bup.util.HttpMessageInfo). messageInfo contains additional information about the message, including whether the message is sent over HTTP or HTTPS, as well as the original request received from the client before any changes made by previous filters. If the javascript returns an object of type io.netty.handler.codec.http.HttpResponse, the HTTP request will "short-circuit" and return the response immediately.

Example: Modify User-Agent header

curl -i -X POST -H 'Content-Type: text/plain' -d "request.headers().remove('User-Agent'); request.headers().add('User-Agent', 'My-Custom-User-Agent-String 1.0');" http://localhost:8080/proxy/8081/filter/request
Response filters

Javascript response filters have access to the variables response (type io.netty.handler.codec.http.HttpResponse), contents (type com.browserup.bup.util.HttpMessageContents), and messageInfo (type com.browserup.bup.util.HttpMessageInfo). As in the request filter, messageInfo contains additional information about the message.

Example: Modify response body

curl -i -X POST -H 'Content-Type: text/plain' -d "contents.setTextContents('<html><body>Response successfully intercepted</body></html>');" http://localhost:8080/proxy/8081/filter/response

SSL Support

BrowserUp Proxy supports full MITM: For most users, MITM will work out-of-the-box with default settings. Install the ca-certificate-rsa.cer file in your browser or HTTP client to avoid untrusted certificate warnings. Generally, it is safer to generate your own private key, rather than using the .cer files distributed with BrowserUp Proxy. See the README file in the mitm module for instructions on generating or using your own root certificate and private key with MITM.

Note: DO NOT permanently install the .cer files distributed with BrowserUp Proxy in users' browsers. They should be used for testing only and must not be used with general web browsing.

If you're doing testing with Selenium, you'll want to make sure that the browser profile that gets set up by Selenium not only has the proxy configured, but also has the CA installed. Unfortunately, there is no API for doing this in Selenium; it must be done manually for each browser and environment.

NodeJS Support

We are compatible with the browsermob proxy, so you could probably fork this and get it going [https://www.npmjs.com/package/browsermob-proxy-api]

Logging

When running in stand-alone mode, the proxy loads the default logging configuration from the conf/bup-logging.yaml file. To increase/decrease the logging level, change the logging entry for com.browserup.bup.

DNS Resolution

The BrowserUpProxyServer implementation uses native DNS resolution by default, but supports custom DNS resolution and advanced DNS manipulation. See the ClientUtil class for information on DNS manipulation using the dnsjava resolver.

Building the latest from source

You'll need gradle. Please see here how to install gradle on your system.
[~]$ gradle build --info

Also you can use gradle wrapper:
[~]$ ./gradlew build --info

When you build the latest code from source, you'll have access to the latest snapshot release. To use the SNAPSHOT version in your code, modify the version in your maven pom:

    <dependency>
        <groupId>com.browserup</groupId>
        <artifactId>browserup-proxy-core</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <scope>test</scope>
    </dependency>

Or for gradle:

testImplementation 'com.browserup:browserup-proxy-core:1.0.0-SNAPSHOT'
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