Added Avram::Join::Raw. (#1048)

src/avram/join.cr

@@ -76,4 +76,60 @@ module Avram::Join
       "FULL"
     end
   end
+
+  class Raw
+    @clause : String
+
+    def self.new(statement : String, *bind_vars)
+      new(statement, args: bind_vars.to_a)
+    end
+
+    def initialize(statement : String, *, args bind_vars : Array)
+      ensure_enough_bind_variables_for!(statement, bind_vars)
+      @clause = build_clause(statement, bind_vars)
+    end
+
+    def prepare(placeholder_supplier : Proc(String)) : String
+      @clause
+    end
+
+    def to_sql : String
+      @clause
+    end
+
+    def clone : self
+      self
+    end
+
+    private def ensure_enough_bind_variables_for!(statement, bind_vars)
+      bindings = statement.chars.select(&.== '?')
+      if bindings.size != bind_vars.size
+        raise "wrong number of bind variables (#{bind_vars.size} for #{bindings.size}) in #{statement}"
+      end
+    end
+
+    private def build_clause(statement, bind_vars)
+      bind_vars.each do |arg|
+        encoded_arg = prepare_for_execution(arg)
+        statement = statement.sub('?', encoded_arg)
+      end
+      statement
+    end
+
+    private def prepare_for_execution(value)
+      if value.is_a?(Array)
+        "'#{PQ::Param.encode_array(value)}'"
+      else
+        escape_if_needed(value)
+      end
+    end
+
+    private def escape_if_needed(value)
+      if value.is_a?(String) || value.is_a?(Slice(UInt8))
+        PG::EscapeHelper.escape_literal(value)
+      else
+        value
+      end
+    end
+  end
 end

src/avram/query_builder.cr

@@ -8,6 +8,7 @@ class Avram::QueryBuilder
   @offset : Int32?
   @wheres = [] of Avram::Where::Condition
   @joins = [] of Avram::Join::SqlClause
+  @raw_joins = [] of Avram::Join::Raw
   @orders = [] of Avram::OrderByClause
   @groups = [] of ColumnName
   @selections : String = "*"
@@ -318,6 +319,15 @@ class Avram::QueryBuilder
     @joins.uniq(&.to_sql)
   end
 
+  def join(raw_join_clause : Avram::Join::Raw) : self
+    @raw_joins << raw_join_clause
+    self
+  end
+
+  def joins : Array(Avram::Join::Raw)
+    @raw_joins.uniq(&.to_sql)
+  end
+
   private def joins_sql : String
     joins.join(" ", &.to_sql)
   end

src/avram/queryable.cr

@@ -124,6 +124,14 @@ module Avram::Queryable(T)
     clone.tap &.query.join(join_clause)
   end
 
+  def join(statement : String, *bind_vars) : self
+    join(statement, args: bind_vars.to_a)
+  end
+
+  def join(statement : String, *, args bind_vars : Array) : self
+    clone.tap &.query.join(Avram::Join::Raw.new(statement, args: bind_vars))
+  end
+
   def where(column : Symbol, value) : self
     clone.tap &.query.where(Avram::Where::Equal.new(column, value.to_s))
   end