Options

Tidy includes a large number of configuration options, only a few of which are relevant in the context of this book.

Two options deal with output formats applicable for web scraping: output-html and output-xhtml. Both are specified as boolean values. These options are mutually exclusive, meaning that only one can be set to true at any given time. Generally output-xhtml is preferable, but may not always be feasible to use. It’s important to compare tidy output to the original document to confirm that correction of document malformations hasn’t resulted in data loss.

Document encoding is one area where issues may arise later depending on the configuration of tidy when it’s used. For example, the XMLReader extension uses UTF-8 encoding internally, which may be problematic if your input document’s encoding conflicts. input-encoding and output-encoding can be used to control the assumed encoding for each.

Other options are useful mainly for debugging purposes and should generally be turned off in production environments. This is a good reason for subclassing the tidy class to control default option values, so that two separate sets are easily accessible for different development environments.

Three ofthese options are indent, indent-spaces, and indent-attributes. The first of these, indent, is a boolean value indicating whether tidy should apply indentation to make the hierarchical relationships between elements more visually prominent. indent-spaces is an integer containing the number of whitespace characters used to denote a single level of indentation, defaulting to 2. Lastly, indent-attributes is a boolean value indicating whether each individual attribute within an element should begin on a new line.

Speaking of attributes, sort-attributes can be set to alpha in order to have element attributes be sorted alphabetically. It is set to none by default, which disables sorting.

If lines within a document tend to be long and difficult to read, the wrap option may be useful. It’s an integer representing the number of characters per line that tidy should allow before forcing a new line. It is set to 68 by default and can be disabled entirely by being set to 0.

Flaving no empty lines to separate blocks can also make markup difficult to read, vertical-space is a boolean value intended to help with this by adding empty lines for readability. It is disabled by default.