Challenge checker

What is it?

A Challenge checker uses program code that checks if a user has fullfilled the requirements of a challenge cache. Per the guidelines of Geocaching.com a challenge cache published after April 21, 2015, must include a link to a web-based challenge checker. So far Project-GC is the only allowed challenge checker. More general information about challenge caches is available in the article challenge caches, for example information about challenge exceptions.

How does it work?

A challenge checker consists of two parts: a challenge checker script and a tag. The script is a piece of program code written in the programming language Lua. The script checks for a certain condition, for example a script can check if the user has found 100 mystery caches. Another script can check if a user found a cache on 365 calendar days. A tag associates one or more scripts with a specific challenge cache, and defines (customizes) cache type and quantity for a script to match the challenge cache.

The tag links a checker script, a challenge cache, and (optionally) a set of parameters for the checker script. This means that the same script can be used both for a challenge that requires the user to have found 100 mystery caches and a challenge that requires the user to have found 1000 traditional caches, since the cache type and quantity of finds required is specified in the tag.

The same checker script can be used for multiple challenge caches (For instance, most calendar challenges are handled by the same checker script). The tag is what makes this possible.

Project-GC also calculates how difficult a challenge is, more information at: Challenge difficulty

Challenge Checker image

It is preferred to link the challenge checker with the supplied image since it contains extra information for the users. An example of such an image can be seen below. The image linked in the wiki are static due to technical reasons, the images on cache pages are not and will be updated with current numbers automatically.

In the top left corner is an icon of a skull and crossbones with a number, this is the calculated challenge difficulty.

Below the challenge difficulty is a red circle for challenges were the saved result for the authenticated user is not fulfilled. For challenges that the user have ran the checker and fulfilled the challenge it is a green checkmark, the green checkmark can be a false positive in cases were the user has ran the checker previously but since lost their qualifications. If the user has found the challenge the result is replaced by an emoji.

To the right are the number of times the checker has been ran with a "fulfilled" or "not fulfilled" result. There are anti-spam measurements applied to these counters but it should not be viewed as number of people that have completed the challenge since both the green and red counters can increase multiple times by the same account.

Checker Requests

Challenge checkers are created by volunteers and can be requested in the Checker request forums, it is important to read the READ FIRST-post before posting a request.

Disabled checkers

Project-GC has a system for disabling the challenge checker if the cache lacks the Challenge-attribute, this is because the challenge-attribute is mandatory per the guidelines.

FAQ

Visit Project-GC's FAQ to find answers to many of the most common questions.

Related paid membership features

If a user have a paid membership Project-GC automatically runs challenge checkers for the user in the background. See the article about Auto-challenge-checkers for more information.

With a paid membership there is no limit on how many challenge checkers you can run. Non paying users are only allowed to run 10 challenge checkers per 24 hours. The limit is a rolling rate limit.

The Map of challenge caches is a tool that can show the challenge caches of the world on a map. Different filters can be applied.

Tools

The checker script system can be used to create different tools to check for statistics that are not otherwise available at the site. See Tools in the checker system for more information.