Using the Link Checker

On the Ares web pages, the supply option "The Item will link to a website" allows Instructors adding reserve Items to add a URL for students to access a web page or website. The default Document Type for these Items is Web Page Link. The Link Checker is a tool that can automatically check the validity of URLs submitted as reserve Items. The Link Checker form displays a list of the web links that the Ares System Manager could not verify as valid.

Viewing Link Checker Items

To use the Link Checker to monitor and correct web links:

1. From the Ares home screen, click the System tab then click Link Checker.
2. Any Items that have failed the Link Checker will be displayed in the Error tab.
3. To view the link, click on the link under the Location column.
4. To correct a link, double-click on the Item in the grid to open the Item form.
5. Correct the link in the Location field, and save and close the Item form.
6. The corrected link will display in the Link Checker grid.
7. To track the corrected link, select the Item in the grid and click the Retry button. The Item will move from the Error grid to the Retry grid.
8. When the Link Checker runs again, Items with valid links will be removed from the Error and Retry grids.

Common HTTP Codes and Descriptions

Code	Description	Error
500	Internal Server Error	There is a problem with the website's server.
404	Not Found	The web server cannot find the resource.
0	Name Resolution Error	An invalid server name.
408	Timeout Error	The server did not respond in time.
301	Moved Permanently	The data requested has been assigned a new URI, the change is permanent.

How Link Checker Works with the Database

The link check process starts by clearing all existing records from the LinkCheck table, and then retrieving all the items that meet the following criteria:

• DocumentType is WebLink
• Location is not empty
• Inactive date is in the future
• At a status of Item Available on Electronic Reserves or Item Activation Pending

For each item, Link Checker tries to resolve the URL in Location and put the resulting httpcode and description in the LinkCheck table. It adds a status of OK if the link is resolved, ERROR if not, or IGNORE if the link was not checked because the link domain matched the customization key LinkCheckerIgnoreDomains. Success (the status of OK described above) is defined by the LinkCheckerHTTPCodeSuccess customization key. A trigger on Items table, TR_Items_LocationChange, removes records from the LinkCheck table when their corresponding Items record is deleted or has its Location property updated.

Database Fields on the Link Checker Form

The fields in this form come from the LinkCheck table.

Field Name	Database Field Name
Item Id	ItemID
Location	This is the website URL Link
Status Time	StatusTime
Http Code	HTTPCode
Http Description	HTTPDescription