From 9db2c9a45604fba60b999fdcd920aeea44833b7f Mon Sep 17 00:00:00 2001
From: Thomas Leitner <t_leitner@gmx.at>
Date: Tue, 24 Sep 2024 10:37:41 +0200
Subject: [PATCH] Add Document#write_to_string for easily writing the document
 to a string

---
 CHANGELOG.md                  | 1 +
 lib/hexapdf/document.rb       | 9 +++++++++
 test/hexapdf/test_document.rb | 9 +++++++++
 3 files changed, 19 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 22ed8fb3..8dd6a7a3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 * [HexaPDF::Task::MergeAcroForm] for merging AcroForm information for imported
   pages
+* [HexaPDF::Document#write_to_string] for easily writing a document to a String
 
 ### Changed
 
diff --git a/lib/hexapdf/document.rb b/lib/hexapdf/document.rb
index a4af2c09..3c9982ca 100644
--- a/lib/hexapdf/document.rb
+++ b/lib/hexapdf/document.rb
@@ -786,6 +786,15 @@ def write(file_or_io, incremental: false, validate: true, update_fields: true, o
       end
     end
 
+    # Writes the document to a string and returns the string.
+    #
+    # See #write for further information and details on the available arguments.
+    def write_to_string(**args)
+      io = StringIO.new(''.b)
+      write(io)
+      io.string
+    end
+
     def inspect #:nodoc:
       "<#{self.class.name}:#{object_id}>"
     end
diff --git a/test/hexapdf/test_document.rb b/test/hexapdf/test_document.rb
index 8a006eb4..efb8353d 100644
--- a/test/hexapdf/test_document.rb
+++ b/test/hexapdf/test_document.rb
@@ -595,4 +595,13 @@
       refute(dupped.encrypted?)
     end
   end
+
+  it "writes the document to a string" do
+    doc = HexaPDF::Document.new
+    doc.trailer.info[:test] = :test
+    str = doc.write_to_string(update_fields: false)
+    assert_equal(Encoding::ASCII_8BIT, str.encoding)
+    doc = HexaPDF::Document.new(io: StringIO.new(str))
+    assert_equal(:test, doc.trailer.info[:test])
+  end
 end