Merge pull request #949 from cntral/read_content_in_chunks

Read HTML string and generated PDF file in chunks.

lib/wicked_pdf.rb

@@ -41,16 +41,22 @@ def pdf_from_string(string, options = {})
     options.merge!(WickedPdf.config) { |_key, option, _config| option }
     string_file = WickedPdfTempfile.new('wicked_pdf.html', options[:temp_path])
     string_file.binmode
-    string_file.write(string)
+    string_io = StringIO.new(string)
+    until string_io.eof?
+      string_file.write(string_io.read(1024 * 1024)) # Read 1 MB chunks at a time to avoid `Errno::EINVAL` errors like `Invalid argument @ io_fread` and `Invalid argument @ io_write`.
+    end
     string_file.close
 
     pdf = pdf_from_html_file(string_file.path, options)
     pdf
+  rescue Errno::EINVAL => e
+    Rails.logger.error '[wicked_pdf] The HTML file is too large! Try reducing the size or using the return_file option instead.'
+    raise e
   ensure
     string_file.close if string_file
   end
 
-  def pdf_from_url(url, options = {})
+  def pdf_from_url(url, options = {}) # rubocop:disable Metrics/PerceivedComplexity
     # merge in global config options
     options.merge!(WickedPdf.config) { |_key, option, _config| option }
     generated_pdf_file = WickedPdfTempfile.new('wicked_pdf_generated_file.pdf', options[:temp_path])
@@ -75,11 +81,19 @@ def pdf_from_url(url, options = {})
     end
     generated_pdf_file.rewind
     generated_pdf_file.binmode
-    pdf = generated_pdf_file.read
+
+    pdf = ''
+    until generated_pdf_file.eof?
+      pdf << generated_pdf_file.read(1024 * 1024) # Read 1 MB chunks at a time to avoid `Errno::EINVAL` errors like `Invalid argument @ io_fread` and `Invalid argument @ io_write`.
+    end
+
     raise "Error generating PDF\n Command Error: #{err}" if options[:raise_on_all_errors] && !err.empty?
     raise "PDF could not be generated!\n Command Error: #{err}" if pdf && pdf.rstrip.empty?
 
     pdf
+  rescue Errno::EINVAL => e
+    Rails.logger.error '[wicked_pdf] The PDF file is too large! Try reducing the size or using the return_file option instead.'
+    raise e
   rescue StandardError => e
     raise "Failed to execute:\n#{command}\nError: #{e}"
   ensure