1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327
//! This module provides utilities for composing multipart mails. //! //! While the `Mail` type on itself can represent any multipart //! mail most mails have a certain pattern to their structure, //! consisting mainly of `multipart/mixed` for attachments, //! `multipart/alternative` for alternative bodies and //! `multipart/related` for including embedded resources which //! can be used in the mail bodies like e.g. a logo. //! //! This module provides the needed utilities to more simply //! create a `Mail` instance which represents this kind of //! mails. //-------------------------------------------------------------\\ // NOTE: Implementations for creating (composing) mails are || // split from the type dev, and normal impl blocks and placed || // in the later part of the file for better readability. || //-------------------------------------------------------------// use media_type::{MULTIPART, ALTERNATIVE, RELATED, MIXED}; use vec1::Vec1; use headers::{ HeaderKind, headers, header_components::{ Disposition, DispositionKind, MediaType } }; use crate::{ mail::Mail, resource::Resource }; /// Parts used to create a mail body (in a multipart mail). /// /// This type contains a `Resource` which is normally used /// to create a alternative body in a `multipart/alternative` /// section. As well as a number of "embeddings" which depending /// on there disposition can are either used as attachments /// or embedded resource to which the body can referre to /// by it's content id. #[derive(Debug)] pub struct BodyPart { /// A body created by a template. pub resource: Resource, /// A number of embeddings which should be displayed inline. /// /// This is normally used to embed images then displayed in /// a html body. It is not in the scope of this part of the /// library to bind content id's to resources to thinks using /// them to display the embeddings. This part of the library /// does "just" handle that they are correctly placed in the /// resulting Mail. The `mail-templates` crate provides more /// functionality for better ergonomics. /// /// Note that embeddings placed in a `BodyPart` instance are potentially /// only usable in the body specified in the same `BodyPart` instance. pub inline_embeddings: Vec<Resource>, /// A number of embeddings which should be treated as attachments. /// /// Attachments of a `BodyPart` instance will be combined with /// the attachments of other instances and the ones in the /// `MailParts` instance. pub attachments: Vec<Resource> } /// Parts which can be used to compose a multipart mail. /// /// This can be used to crate a mail, possible having /// attachments with multiple alternative bodies having /// embedded resources which can be referred to by the /// bodies with content ids. This embeddings can be both /// body specific or shared between bodies. /// /// # Limitations /// /// Any non alternative body will be either an attachment /// or an body with a inline disposition header in a /// `multipart/related` body. Which means you can not /// use this mechanism to e.g. create a `multipart/mixed` /// body with multiple disposition inline sub-bodies /// which should be displayed side-by-side. Generally this /// is not a very good way to create a mail, through a /// valid way nevertheless. /// pub struct MailParts { /// A vector of alternative bodies /// /// A typical setup would be to have two alternative bodies one text/html and /// another text/plain as fallback (for which the text/plain body would be /// the first in the vec and the text/html body the last one). /// /// Note that the order in the vector /// a additional text/plainis /// the same as the order in which they will appear in the mail. I.e. /// the first one is the last fallback while the last one should be /// shown if possible. pub alternative_bodies: Vec1<BodyPart>, /// A number of embeddings which should be displayed inline. /// /// This is normally used to embed images then displayed in /// a html body. It is not in the scope of this part of the /// library to bind content id's to resources to thinks using /// them to display the embeddings. This part of the library /// does "just" handle that they are correctly placed in the /// resulting Mail. The `mail-templates` crate provides more /// functionality for better ergonomics. pub inline_embeddings: Vec<Resource>, /// A number of embeddings which should be treated as attachments pub attachments: Vec<Resource> } //-------------------------------------------------------\\ // implementations for creating mails are from here on || //-------------------------------------------------------// impl MailParts { /// Create a `Mail` instance based on this `MailParts` instance. /// /// /// If this instance contains any attachments then the /// returned mail will be a `multipart/mixed` mail with /// the first body containing the actual mail and the /// other bodies containing the attachments. /// /// If the `MailParts.inline_embeddings` is not empty then /// the mail will be wrapped in `multipart/related` (inside /// any potential `multipart/mixed`) containing the /// actual mail in the first body and the inline embeddings /// in the other bodies. /// /// The mail will have a `multipart/alternative` body /// if it has more then one alternative body /// (inside a potential `multipart/related` inside a /// potential `multipart/mixed` body). This body contains /// one sub-body for each `BodyPart` instance in /// `MailParts.alternative_bodies`. /// /// Each sub-body created for a `BodyPart` will be wrapped /// inside a `multipart/related` if it has body specific /// embeddings (with content disposition inline). pub fn compose(self) -> Mail { let MailParts { alternative_bodies, inline_embeddings, attachments } = self; let mut attachments = attachments.into_iter() .map(|atta| atta.create_mail_with_disposition(DispositionKind::Attachment)) .collect::<Vec<_>>(); let mut alternatives = alternative_bodies.into_iter() .map(|body| body.create_mail(&mut attachments)) .collect::<Vec<_>>(); //UNWRAP_SAFE: bodies is Vec1, i.e. we have at last one let mail = alternatives.pop().unwrap(); let mail = if alternatives.is_empty() { mail } else { mail.wrap_with_alternatives(alternatives) }; let mail = if inline_embeddings.is_empty() { mail } else { let related = inline_embeddings.into_iter() .map(|embedding| { embedding.create_mail_with_disposition(DispositionKind::Inline) }) .collect::<Vec<_>>(); mail.wrap_with_related(related) }; let mail = if attachments.is_empty() { mail } else { mail.wrap_with_mixed(attachments) }; mail } } impl BodyPart { /// Creates a `Mail` instance from this `BodyPart` instance. /// /// All embeddings in `BodyPart.embeddings` which have a /// attachment content disposition are placed into the /// `attachments_out` parameter, as attachments should /// always be handled on the outer most level but the /// produced mail is likely not the outer most level. /// /// This will create a non-multipart body for the /// body `Resource`, if there are any embeddings which /// have a `Inline` disposition that body will be /// wrapped into a `multipart/related` body containing /// them. pub fn create_mail( self, attachments_out: &mut Vec<Mail>, ) -> Mail { let BodyPart { resource, inline_embeddings, attachments } = self; let body = resource.create_mail(); for attachment in attachments.into_iter() { let mail = attachment.create_mail_with_disposition(DispositionKind::Attachment); attachments_out.push(mail) } if inline_embeddings.is_empty() { body } else { let related = inline_embeddings.into_iter() .map(|embedding| { embedding.create_mail_with_disposition(DispositionKind::Inline) }) .collect::<Vec<_>>(); body.wrap_with_related(related) } } } impl Resource { /// Create a `Mail` instance representing this `Resource`. /// /// This is not a complete mail, i.e. it will not contain /// headers like `From` or `To` and in many cases the /// returned `Mail` instance will be wrapped into other /// mail instances adding alternative bodies, embedded /// resources and attachments. pub fn create_mail(self) -> Mail { Mail::new_singlepart_mail(self) } pub fn create_mail_with_disposition(self, disposition_kind: DispositionKind) -> Mail { let mut mail = self.create_mail(); //TODO[1.0] grab meta from resource let disposition = Disposition::new(disposition_kind, Default::default()); mail.insert_header(headers::ContentDisposition::body(disposition)); mail } } impl Mail { /// Create a `multipart/mixed` `Mail` instance containing this mail as /// first body and one additional body for each attachment. /// /// Normally this is used with embeddings having a attachment /// disposition creating a mail with attachments. pub fn wrap_with_mixed(self, other_bodies: Vec<Mail>) -> Mail { let mut bodies = other_bodies; bodies.push(self); new_multipart(&MIXED, bodies) } /// Create a `multipart/alternative` `Mail` instance containing this /// mail as the _main_ body with given alternatives. /// /// The "priority" of alternative bodies is ascending with the body /// which should be shown only if all other bodies can't be displayed /// first. I.e. the order is the same order as /// specified by `multipart/alternative`. /// This also means that _this_ body will be the last body as it is /// meant to be the _main_ body. pub fn wrap_with_alternatives(self, alternates: Vec<Mail>) -> Mail { let mut bodies = alternates; //TODO[opt] accept iter and prepend instead of insert in vec bodies.insert(0, self); new_multipart(&ALTERNATIVE, bodies) } /// Creates a `multipart/related` `Mail` instance containing this /// mail first and then all related bodies. pub fn wrap_with_related(self, related: Vec<Mail>) -> Mail { let mut bodies = related; bodies.insert(0, self); new_multipart(&RELATED, bodies) } } /// Creates a `multipart/<sub_type>` mail with given bodies. /// /// # Panic /// /// If `sub_type` can not be used to create a multipart content /// type this will panic. fn new_multipart(sub_type: &'static str, bodies: Vec<Mail>) -> Mail { let content_type = MediaType::new(MULTIPART, sub_type) .unwrap(); Mail::new_multipart_mail(content_type, bodies) }