URL Types

This page defines and discusses varieties of URLs that will be encountered when working with vendor URLs. Each URL is a combination of these types. To illustrate this, some of the same URLs are used in multiple examples in the charts below.

Starting Point URLs

The goal in understanding vendor URLs is to determine the starting point URL. A starting point URL is a persistent, durable URL that connects a browser to a resource. This is the URL utilized in your OPAC, Web site, database, etc. to provide access to a resource. Ultimately, our goal is to determine starting point URLs.

The concept of the starting point URL is important for two reasons:

  1. Many vendor URLs become transformed by programming scripts when they are selected, so that the destination URL is different from the starting point URL. In these cases, the destination URL is not persistent. It cannot be copied and pasted into your application to be used again, because it will fail.
  2. Many vendors sites feature title lists that use URLs that are not structured to be persistent if used by their customers. If you use the URLs featured on these lists, your connections may fail.

The URLs described below are four different types of starting point URLs.

Static URL

Definition: A URL that connects to a desination without calling a script.

Example: http://muse.jhu.edu/journals/american_literature/

Discussion A static URL is a persistent, durable URL. No programming scripts are generated when a static URL is selected. Therefore the destination URL is identical to the starting point URL. A static URL is always a starting point URL.

Dynamic URL

Definition: A URL that processes a script to connect to a destination.

Example: http://www.springerlink.com/link.asp?id=100408

Discussion: Dynamic URLs are becoming increasingly common with vendors and should be analyzed carefully. Most become transformed at the destination.

For example, this URL, http://firstsearch.oclc.org/dbname=WorldCat;done=referer;FSIP becomes transformed to this:


In this case, the destination URL is not persistent and therefore should not be used as a starting point URL.

Directory URL

Definition: A URL without a filename that points to a directory's default file.

Example: http://muse.jhu.edu/journals/american_literature/

Discussion:A directory URL may be either static or dynamic. A dynamic directory URL calls a script from a file given the Web server's default file name, e.g., default.asp. The script may be a simple redirect or something more complex.

There are two rules for the correct construction of directory URLs.

1. Complete the URL with a trailing slash [/] as long as the URL is static. Without the trailing slash, it will take two requests of the browser to retrieve the file from the server. With the trailing slash, one request of the browser will retrieve the file. This conserves the server resources of our vendors, speeds up access times for our users, and reduces network traffic.

Correct: http://muse.jhu.edu/journals/american_literature/

Incorrect: http://muse.jhu.edu/journals/american_literature

2. Omit the default file name. A default file is a file given a name that is configured to be located by a Web server by default. Examples include index.html, index.htm, default.htm, default.asp etc. This file name is meant to be unseen, and does not provide any semantic cues about the content of the file.

Preferred: http://muse.jhu.edu/journals/american_literature/

Not preferred: http://muse.jhu.edu/journals/american_literature/index.html

Formula URL

Definition: A required structure that adheres to a specific format and must be used to connect to a destination.


Discussion: A formula URL may be either static or dynamic. If dynamic, the URL may be either unchanged or transformed at the destination, for example:

Unchanged at the destination


Transformed at the destination

This URL, http://firstsearch.oclc.org/dbname=WorldCat;done=referer;FSIP

becomes transformed to this


Dynamic formula URLs are commonly used by vendors. Unless the case is obvious, you should always examine a vendor's site for instructions on constructing formula URLs for your starting point URLs.

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