Redis command arguments

How Redis commands expose their documentation programmatically

TheCOMMAND DOCS command returns documentation-focused information about available Redis commands.The map reply that the command returns includes thearguments key.This key stores an array that describes the command's arguments.

Every element in thearguments array is a map with the following fields:

• name: the argument's name, always present.The name of an argument is given for identification purposes alone.It isn't displayed during the command's syntax rendering.The same name can appear more than once in the entire argument tree, but it is unique compared to other sibling arguments' names.This allows obtaining a unique identifier for each argument (the concatenation of all names in the path from the root to any argument).
• display_text: the argument's display string, present in arguments that have a displayable representation (all arguments that aren't oneof/block).This is the string used in the command's syntax rendering.
• type: the argument's type, always present.An argument must have one of the following types:
  • string: a string argument.
  • integer: an integer argument.
  • double: a double-precision argument.
  • key: a string that represents the name of a key.
  • pattern: a string that represents a glob-like pattern.
  • unix-time: an integer that represents a Unix timestamp.
  • pure-token: an argument is a token, meaning a reserved keyword, which may or may not be provided.Not to be confused with free-text user input.
  • oneof: the argument is a container for nested arguments.This type enables choice among several nested arguments (see theXADD example below).
  • block: the argument is a container for nested arguments.This type enables grouping arguments and applying a property (such asoptional) to all (see theXADD example below).
• key_spec_index: this value is available for every argument of thekey type.It is a 0-based index of the specification in the command'skey specifications that corresponds to the argument.
• token: a constant literal that precedes the argument (user input) itself.
• summary: a short description of the argument.
• since: the debut Redis version of the argument (or for module commands, the module version).
• deprecated_since: the Redis version that deprecated the command (or for module commands, the module version).
• flags: an array of argument flags.Possible flags are:
  • optional: denotes that the argument is optional (for example, theGET clause of theSET command).
  • multiple: denotes that the argument may be repeated (such as thekey argument ofDEL).
  • multiple-token: denotes the possible repetition of the argument with its preceding token (seeSORT'sGET pattern clause).
• value: the argument's value.For arguments types other thanoneof andblock, this is a string that describes the value in the command's syntax.For theoneof andblock types, this is an array of nested arguments, each being a map as described in this section.

Example

The trimming clause ofXADD, i.e.,[MAXLEN|MINID [=|~] threshold [LIMIT count]], is represented at the top-level asblock-typed argument.

It consists of four nested arguments:

1. trimming strategy: this nested argument has anoneof type with two nested arguments.Each of the nested arguments,MAXLEN andMINID, is typed aspure-token.
2. trimming operator: this nested argument is an optionaloneof type with two nested arguments.Each of the nested arguments,= and~, is apure-token.
3. threshold: this nested argument is astring.
4. count: this nested argument is an optionalinteger with atoken (LIMIT).

Here'sXADD's arguments array:

1) 1) "name"   2) "key"   3) "type"   4) "key"   5) "value"   6) "key"2)  1) "name"    2) "nomkstream"    3) "type"    4) "pure-token"    5) "token"    6) "NOMKSTREAM"    7) "since"    8) "6.2"    9) "flags"   10) 1) optional3) 1) "name"   2) "trim"   3) "type"   4) "block"   5) "flags"   6) 1) optional   7) "value"   8) 1) 1) "name"         2) "strategy"         3) "type"         4) "oneof"         5) "value"         6) 1) 1) "name"               2) "maxlen"               3) "type"               4) "pure-token"               5) "token"               6) "MAXLEN"            2) 1) "name"               2) "minid"               3) "type"               4) "pure-token"               5) "token"               6) "MINID"               7) "since"               8) "6.2"      2) 1) "name"         2) "operator"         3) "type"         4) "oneof"         5) "flags"         6) 1) optional         7) "value"         8) 1) 1) "name"               2) "equal"               3) "type"               4) "pure-token"               5) "token"               6) "="            2) 1) "name"               2) "approximately"               3) "type"               4) "pure-token"               5) "token"               6) "~"      3) 1) "name"         2) "threshold"         3) "type"         4) "string"         5) "value"         6) "threshold"      4)  1) "name"          2) "count"          3) "type"          4) "integer"          5) "token"          6) "LIMIT"          7) "since"          8) "6.2"          9) "flags"         10) 1) optional         11) "value"         12) "count"4) 1) "name"   2) "id_or_auto"   3) "type"   4) "oneof"   5) "value"   6) 1) 1) "name"         2) "auto_id"         3) "type"         4) "pure-token"         5) "token"         6) "*"      2) 1) "name"         2) "id"         3) "type"         4) "string"         5) "value"         6) "id"5) 1) "name"   2) "field_value"   3) "type"   4) "block"   5) "flags"   6) 1) multiple   7) "value"   8) 1) 1) "name"         2) "field"         3) "type"         4) "string"         5) "value"         6) "field"      2) 1) "name"         2) "value"         3) "type"         4) "string"         5) "value"         6) "value"