Custom IO in and IO out

bin/cli.cr

@@ -80,7 +80,9 @@ class CLI < Admiral::Command
 
     options[:empty_value_replace_char] = flags.empty_value_replace_char
 
-    Csv::To::Json.run(io, options)
+    out_io = STDOUT
+
+    Csv::To::Json.run(io, out_io, options)
   end
 end
 

spec/csv-to-json_spec.cr

@@ -20,5 +20,67 @@ describe Csv::To::Json do
     it "will respond to #run" do
       Csv::To::Json.responds_to?(:run).should be_true
     end
+
+    context "with io object" do
+      it "will try to parse the CSV object and output to out_io" do
+        in_io = IO::Memory.new("field 1,field 2\nvalue 1,\n")
+        out_io = IO::Memory.new()
+
+        Csv::To::Json.run(in_io, out_io)
+
+        out_io.seek(0)
+        out_io.to_s.should contain("[\n{\"field 1\":\"value 1\",\"field 2\":\"\"}\n]\n")
+      end
+    end
+
+    context "with options" do
+      context "with empty_value_replace_char option" do
+        it "will replace each empty value with the empty_value_replace_char char" do
+          in_io = IO::Memory.new("field 1,field 2\nvalue 1,\n")
+          out_io = IO::Memory.new()
+
+          options = {
+            :empty_value_replace_char => "blah"
+          }
+
+          Csv::To::Json.run(in_io, out_io, options)
+
+          out_io.seek(0)
+          out_io.to_s.should contain("blah")
+        end
+      end
+
+      context "with delimiter option" do
+        it "will parse on different delimiter" do
+          in_io = IO::Memory.new("field 1\tfield 2\nvalue 1\t\n")
+          out_io = IO::Memory.new()
+
+          options = {
+            :delimiter => '\t'
+          }
+
+          Csv::To::Json.run(in_io, out_io, options)
+
+          out_io.seek(0)
+          out_io.to_s.should contain("[\n{\"field 1\":\"value 1\",\"field 2\":\"\"}\n]\n")
+        end
+      end
+
+      context "with quote_char option" do
+        it "will parse on different quote char" do
+          in_io = IO::Memory.new("field 1,!\"field 2\"!\nvalue 1,\n")
+          out_io = IO::Memory.new()
+
+          options = {
+            :quote_char => '!'
+          }
+
+          Csv::To::Json.run(in_io, out_io, options)
+
+          out_io.seek(0)
+          out_io.to_s.should contain("[\n{\"field 1\":\"value 1\",\"\\\"field 2\\\"\":\"\"}\n]\n")
+        end
+      end
+    end
   end
 end

src/csv-to-json.cr

@@ -3,20 +3,21 @@ require "csv"
 require "json"
 
 module Csv::To::Json
-  def self.run(io, options = {} of Symbol => String)
+  # Processes a CSV file on *in_io* with *options* and produces a JSON object on *out_io*
+  def self.run(in_io, out_io, options = {} of Symbol => String)
     STDIN.blocking = true
 
-    empty_value_replace_char = options[:empty_value_replace_char]
+    empty_value_replace_char = options.fetch(:empty_value_replace_char, "").as(String)
     tail = options.delete :tail
     delimiter = options.fetch(:delimiter, ',').as(Char)
     quote_char = options.fetch(:quote_char, '"').as(Char)
 
     #file = File.open(csv)
-    csv_io = CSV::Parser.new(io, delimiter, quote_char)
+    csv_io = CSV::Parser.new(in_io, delimiter, quote_char)
 
     header = csv_io.next_row
 
-    puts "["
+    out_io.puts "["
 
     count = 0
     row = csv_io.next_row
@@ -43,7 +44,7 @@ module Csv::To::Json
         }
       end
 
-      print Hash.zip(
+      out_io.print Hash.zip(
         header.as(Array(String)),
         values
       ).to_json
@@ -54,21 +55,21 @@ module Csv::To::Json
         STDERR.puts "\n"
         STDERR.puts "#{ex} at line: #{count + 3}"
 
-        io.seek(-1 * ex.column_number, IO::Seek::Current)
-        STDERR.puts io.read_line
+        in_io.seek(-1 * ex.column_number, IO::Seek::Current)
+        STDERR.puts in_io.read_line
 
         exit 2
       end
 
       # super ugly
       if tail.nil? ? !row.nil? : tail.to_i != count + 1 && !row.nil?
-        puts ","
+        out_io.puts ","
       else
         break
       end
       count += 1
     end
 
-    puts "\n]"
+    out_io.puts "\n]"
   end
 end