http://www.example.com this line should never be modified this link should be injected this custom link should be injected this link should be injected, and marker substituted mailto link should still work HTML entities encoded mailto link should still work ###unknown_field_will_be_kept### http://example.com/index.php?id=1&tx_newsletter_p%5Baction%5D=show&tx_newsletter_p%5Bcontroller%5D=Email&type=1342671779&c=d41d8cd98f00b204e9800998ecf8427e http://example.com/index.php?id=1&tx_newsletter_p%5Baction%5D=unsubscribe&tx_newsletter_p%5Bcontroller%5D=Email&type=1342671779&c=d41d8cd98f00b204e9800998ecf8427e recipient@example.com my custom value http://unknown_field_will_be_kept http://example.com/index.php?id=1&tx_newsletter_p%5Baction%5D=show&tx_newsletter_p%5Bcontroller%5D=Email&type=1342671779&c=d41d8cd98f00b204e9800998ecf8427e http://example.com/index.php?id=1&tx_newsletter_p%5Baction%5D=unsubscribe&tx_newsletter_p%5Bcontroller%5D=Email&type=1342671779&c=d41d8cd98f00b204e9800998ecf8427e recipient@example.com my custom value https://unknown_field_will_be_kept https://example.com/index.php?id=1&tx_newsletter_p%5Baction%5D=show&tx_newsletter_p%5Bcontroller%5D=Email&type=1342671779&c=d41d8cd98f00b204e9800998ecf8427e https://example.com/index.php?id=1&tx_newsletter_p%5Baction%5D=unsubscribe&tx_newsletter_p%5Bcontroller%5D=Email&type=1342671779&c=d41d8cd98f00b204e9800998ecf8427e recipient@example.com my custom value boolean_false= boolean_true=true-ish integer_false= integer_true=true-ish string_false= string_true=true-ish boolean_false=false-ish boolean_true=true-ish integer_false=false-ish integer_true=true-ish string_false=false-ish string_true=true-ish image