Class: Parse::Constraint::StartsWithConstraint

Inherits:

Parse::Constraint

Object
Parse::Constraint
Parse::Constraint::StartsWithConstraint

show all

Defined in:: lib/parse/query/constraints.rb

Overview

Equivalent to using the $regex Parse query operation with a prefix pattern. This is useful for autocomplete functionality and prefix matching.

# Find users whose name starts with "John" User.where(:name.starts_with => "John") # Generates: "name": { "$regex": "^John", "$options": "i" }

# Opt into Unicode-aware case-insensitive matching (Parse Server 8.3.0+ # over REST, MongoDB 6.1+ mongo-direct): User.where(:name.starts_with => { value: "café", unicode: true }) # Generates: "name": { "$regex": "^café", "$options": "iu" }

Instance Attribute Summary

Attributes inherited from Parse::Constraint

#operand, #operation, #operator, #value

Instance Method Summary collapse

#build ⇒ Hash
The compiled constraint.
#starts_with ⇒ StartsWithConstraint
A registered method on a symbol to create the constraint.

Methods inherited from Parse::Constraint

#as_json, constraint_keyword, create, formatted_value, #formatted_value, #initialize, #key, #precedence, #regex_unicode_option, register, #to_s

Constructor Details

This class inherits a constructor from Parse::Constraint

Instance Method Details

#build ⇒ `Hash`

Returns the compiled constraint.

Returns:

(Hash) —
the compiled constraint.

# File 'lib/parse/query/constraints.rb', line 2364

def build
  raw, unicode = regex_unicode_option(@value)
  value = self.class.formatted_value(raw)
  unless value.is_a?(String)
    raise ArgumentError, "#{self.class}: Value must be a string for starts_with constraint"
  end

  # Validate length to prevent performance issues
  if value.length > Parse::RegexSecurity::MAX_PATTERN_LENGTH
    raise ArgumentError, "#{self.class}: Value too long (#{value.length} chars, max #{Parse::RegexSecurity::MAX_PATTERN_LENGTH})"
  end

  # Escape special regex characters in the prefix
  escaped_value = Regexp.escape(value)
  regex_pattern = "^#{escaped_value}"

  { @operation.operand => { :$regex => regex_pattern, :$options => (unicode ? "iu" : "i") } }
end

#starts_with ⇒ `StartsWithConstraint`

A registered method on a symbol to create the constraint. Maps to Parse operator "$regex".

Examples:

q.where :field.starts_with => "prefix"