Parsing Model

Understanding how networkconfparse turns text into a tree makes the query API predictable. This page describes that model.

Lines become a tree

parse reads the configuration line by line and builds a tree of ConfigNode objects. A line is a child of the nearest preceding line with strictly less indentation. The top-level (column 0) lines become the children of the returned Config.

interface GigabitEthernet0/0          <- top-level node
 ip address 10.0.0.1 255.255.255.0    <- child of the interface
 no shutdown                          <- child of the interface

Each node stores its stripped text, its parent, and its children.

Indentation is relative, not fixed

The parser makes no assumption about indent width. It compares the leading whitespace of each line to the lines above it, so a single-space IOS style, a two-space NX-OS style, and even inconsistent indentation all produce the same shape. Tabs are expanded before measuring. A dedent simply re-attaches the following line to the correct ancestor.

Comment and delimiter lines are dropped

Lines whose first non-whitespace character is ! are comments or section delimiters in Cisco platforms. They carry no configuration semantics and are skipped during parsing - they never become nodes. This is safe because the tree's shape is determined entirely by indentation; a ! delimiter is redundant with the dedent that already closes a block.

A ! that appears within a line (for example description has!bang) is part of the text and is preserved.

Banners and certificates are captured as bodies

Some configuration contains freeform, multi-line payloads whose lines are not indentation-structured and may even look like configuration. The parser recognizes these and captures their body verbatim as children of the owning line, rather than mistaking the body for real configuration:

• banner blocks - banner motd ^C followed by body text until the delimiter character reappears. The body (which may contain !, blank lines, or config-looking text) is attached to the banner node; the closing delimiter is dropped.
• Inline certificate data - a certificate ... line inside a crypto pki certificate chain block, whose hex body runs until a standalone quit. The hex is attached to the certificate node; quit is dropped.

Because these bodies are captured as a unit, they never pollute the rest of the tree, and queries over the surrounding configuration behave exactly as expected.