Class: Parse::Constraint::StartsWithConstraint

Inherits:

Constraint

Object
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" }

Instance Method Summary collapse

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

Instance Method Details

#build ⇒ `Hash`

Returns the compiled constraint.

Returns:

(Hash) —
the compiled constraint.

# File 'lib/parse/query/constraints.rb', line 2306

def build
  value = formatted_value
  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 => "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"