Fixed long e-mail message extending 1000 lines.

- Added quoted_printable crate to encode the e-mail messages.
- Change the way the e-mail gets build to use custom part headers.

Cargo.lock

@@ -132,6 +132,7 @@ dependencies = [
  "num-derive 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "oath 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quoted_printable 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "reqwest 0.9.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "ring 0.13.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1602,6 +1603,11 @@ dependencies = [
  "proc-macro2 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "quoted_printable"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "r2d2"
 version = "0.8.3"
@@ -2854,6 +2860,7 @@ dependencies = [
 "checksum quick-error 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "9274b940887ce9addde99c4eee6b5c44cc494b182b97e73dc8ffdcb3397fd3f0"
 "checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
 "checksum quote 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)" = "cdd8e04bd9c52e0342b406469d494fcb033be4bdbe5c606016defbb1681411e1"
+"checksum quoted_printable 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4126fa98c6d7b166e6a29a24ab96721d618759d803df6a8cb35d6140da475b5a"
 "checksum r2d2 0.8.3 (registry+https://github.com/rust-lang/crates.io-index)" = "5d746fc8a0dab19ccea7ff73ad535854e90ddb3b4b8cdce953dd5cd0b2e7bd22"
 "checksum rand 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "552840b97013b1a26992c11eac34bdd778e464601a4c2054b5f0bff7c6761293"
 "checksum rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"

Cargo.toml

@@ -91,6 +91,7 @@ num-derive = "0.2.4"
 lettre = "0.9.0"
 lettre_email = "0.9.0"
 native-tls = "0.2.2"
+quoted_printable = "0.4"
 
 # Template library
 handlebars = "1.1.0"

src/mail.rs

@@ -1,8 +1,9 @@
 use lettre::smtp::authentication::Credentials;
 use lettre::smtp::ConnectionReuseParameters;
 use lettre::{ClientSecurity, ClientTlsParameters, SmtpClient, SmtpTransport, Transport};
-use lettre_email::EmailBuilder;
+use lettre_email::{EmailBuilder,PartBuilder,MimeMultipartType};
 use native_tls::{Protocol, TlsConnector};
+use quoted_printable::encode_to_str;
 
 use crate::api::EmptyResult;
 use crate::auth::{encode_jwt, generate_invite_claims};
@@ -135,11 +136,28 @@ pub fn send_invite_confirmed(address: &str, org_name: &str) -> EmptyResult {
 }
 
 fn send_email(address: &str, subject: &str, body_html: &str, body_text: &str) -> EmptyResult {
+    let html = PartBuilder::new()
+        .body(encode_to_str(body_html))
+        .header(("Content-Type", "text/html; charset=utf-8"))
+        .header(("Content-Transfer-Encoding", "quoted-printable"))
+        .build();
+
+    let text = PartBuilder::new()
+        .body(encode_to_str(body_text))
+        .header(("Content-Type", "text/plain; charset=utf-8"))
+        .header(("Content-Transfer-Encoding", "quoted-printable"))
+        .build();
+
+    let alternative = PartBuilder::new()
+        .message_type(MimeMultipartType::Alternative)
+        .child(text)
+        .child(html);
+
     let email = EmailBuilder::new()
         .to(address)
         .from((CONFIG.smtp_from().as_str(), CONFIG.smtp_from_name().as_str()))
         .subject(subject)
-        .alternative(body_html, body_text)
+        .child(alternative.build())
         .build()
         .map_err(|e| Error::new("Error building email", e.to_string()))?;