Implement sendmail process

4 files changed, 198 insertions, 0 deletions

diff --git a/butl/buildfile b/butl/buildfile
index 6cef7f2..7d33535 100644
--- a/butl/buildfile
+++ b/butl/buildfile
@@ -23,6 +23,7 @@ lib{butl}:                                  \
    {hxx ixx     cxx}{ process             } \
    {hxx            }{ process-details     } \
    {        txx cxx}{ process-run         } \
+   {hxx ixx     cxx}{ sendmail            } \
    {hxx         cxx}{ sha256              } \
    {hxx            }{ small-vector        } \
    {hxx     txx    }{ string-table        } \
diff --git a/butl/sendmail b/butl/sendmail
new file mode 100644
index 0000000..5a380e7
--- /dev/null
+++ b/butl/sendmail
@@ -0,0 +1,92 @@
+// file      : butl/sendmail -*- C++ -*-
+// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef BUTL_SENDMAIL
+#define BUTL_SENDMAIL
+
+#include <string>
+
+#include <butl/export>
+
+#include <butl/process>
+#include <butl/fdstream>
+#include <butl/small-vector>
+
+namespace butl
+{
+  // Send email using the sendmail program.
+  //
+  // Write the body of the email to out. Note that you must explicitly close
+  // it before calling wait(). Throw process_error and io_error (both derive
+  // from system_error) in case of errors.
+  //
+  // Typical usage:
+  //
+  // try
+  // {
+  //   sendmail sm (2,                    // Diagnostics to stderr.
+  //                "",                   // Default From: address.
+  //                "Test subject",
+  //                {"test@example.com"});
+  //
+  //   sm.out << "Test body" << endl;
+  //
+  //   sm.close ();
+  //
+  //   if (!sm.wait ())
+  //     ... // sendmail returned non-zero status.
+  // }
+  // catch (const std::system_error& e)
+  // {
+  //   cerr << "sendmail error: " << e << endl;
+  // }
+  //
+  class LIBBUTL_EXPORT sendmail: public process
+  {
+  public:
+    ofdstream out;
+
+    // Notes:
+    //
+    // - If from is empty then the process user's address is used.
+    //
+    // - The to/cc/bcc addressed should already be quoted if required.
+    //
+    using recipients_type = small_vector<std::string, 1>;
+
+    template <typename E, typename... O>
+    sendmail (E&& err,
+              const std::string& from,
+              const std::string& subject,
+              const recipients_type& to,
+              const recipients_type& cc = recipients_type (),
+              const recipients_type& bcc = recipients_type (),
+              O&&... options);
+
+    // Version with the command line callback (see process_run() for
+    // details).
+    //
+    template <typename C, typename E, typename... O>
+    sendmail (const C&,
+              E&& err,
+              const std::string& from,
+              const std::string& subject,
+              const recipients_type& to,
+              const recipients_type& cc = recipients_type (),
+              const recipients_type& bcc = recipients_type (),
+              O&&... options);
+
+  private:
+    void
+    headers (const std::string& from,
+             const std::string& subj,
+             const recipients_type& to,
+             const recipients_type& cc,
+             const recipients_type& bcc);
+  };
+}
+
+#include <butl/sendmail.ixx>
+
+#endif // BUTL_SENDMAIL
diff --git a/butl/sendmail.cxx b/butl/sendmail.cxx
new file mode 100644
index 0000000..103bab5
--- /dev/null
+++ b/butl/sendmail.cxx
@@ -0,0 +1,40 @@
+// file      : butl/sendmail.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <butl/sendmail>
+
+using namespace std;
+
+namespace butl
+{
+  void sendmail::
+  headers (const std::string& from,
+           const std::string& subj,
+           const recipients_type& to,
+           const recipients_type& cc,
+           const recipients_type& bcc)
+  {
+    if (!from.empty ())
+      out << "From: " << from << endl;
+
+    auto rcp =[this] (const char* h, const recipients_type& rs)
+    {
+      if (!rs.empty ())
+      {
+        bool f (true);
+        out << h << ": ";
+        for (const string& r: rs)
+          out << (f ? (f = false, "") : ", ") << r;
+        out << endl;
+      }
+    };
+
+    rcp ("To",  to);
+    rcp ("Cc",  cc);
+    rcp ("Bcc", bcc);
+
+    out << "Subject: " << subj << endl
+        << endl; // Header/body separator.
+  }
+}
diff --git a/butl/sendmail.ixx b/butl/sendmail.ixx
new file mode 100644
index 0000000..3f6597d
--- /dev/null
+++ b/butl/sendmail.ixx
@@ -0,0 +1,65 @@
+// file      : butl/sendmail.ixx -*- C++ -*-
+// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <utility> // move(), forward()
+
+namespace butl
+{
+  template <typename E, typename... O>
+  inline sendmail::
+  sendmail (E&& err,
+            const std::string& from,
+            const std::string& subj,
+            const recipients_type& to,
+            const recipients_type& cc,
+            const recipients_type& bcc,
+            O&&... options)
+      : sendmail ([] (const char* [], std::size_t) {},
+                  std::forward<E> (err),
+                  from,
+                  subj,
+                  to,
+                  cc,
+                  bcc,
+                  std::forward<O> (options)...)
+  {
+  }
+
+  template <typename C, typename E, typename... O>
+  inline sendmail::
+  sendmail (const C& cmdc,
+            E&& err,
+            const std::string& from,
+            const std::string& subj,
+            const recipients_type& to,
+            const recipients_type& cc,
+            const recipients_type& bcc,
+            O&&... options)
+  {
+    {
+      fdpipe pipe (fdopen_pipe ()); // Text mode seems appropriate.
+
+      process& p (*this);
+      p = process_start (cmdc,
+                         pipe.in,
+                         2, // No output expected so redirect to stderr.
+                         std::forward<E> (err),
+                         dir_path (),
+                         "sendmail",
+                         "-i", // Don't treat '.' as the end of input.
+                         "-t", // Read recipients from headers.
+                         std::forward<O> (options)...);
+
+      out.open (std::move (pipe.out));
+    } // Close pipe.in.
+
+    // Write headers.
+    //
+    // Note that if this throws, then the ofdstream will be closed first
+    // (which should signal to the process we are done). Then the process's
+    // destructor will wait for its termination ignoring any errors.
+    //
+    headers (from, subj, to, cc, bcc);
+  }
+}