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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923
//! De/Serialization for Rust's builtin and std types use serde::{ de::{Deserialize, DeserializeOwned, Deserializer, Error, MapAccess, SeqAccess, Visitor}, ser::{Serialize, Serializer}, }; use std::{ fmt::{self, Display}, iter::FromIterator, marker::PhantomData, str::FromStr, }; use Separator; /// De/Serialize using [Display][] and [FromStr][] implementation /// /// This allows to deserialize a string as a number. /// It can be very useful for serialization formats like JSON, which do not support integer /// numbers and have to resort to strings to represent them. /// /// [Display]: https://doc.rust-lang.org/stable/std/fmt/trait.Display.html /// [FromStr]: https://doc.rust-lang.org/stable/std/str/trait.FromStr.html /// /// # Examples /// /// ``` /// # extern crate serde; /// # #[macro_use] /// # extern crate serde_derive; /// # extern crate serde_json; /// # extern crate serde_with; /// # use std::net::Ipv4Addr; /// #[derive(Deserialize, Serialize)] /// struct A { /// #[serde(with = "serde_with::rust::display_fromstr")] /// address: Ipv4Addr, /// #[serde(with = "serde_with::rust::display_fromstr")] /// b: bool, /// } /// /// # fn main() { /// let v: A = serde_json::from_str(r#"{ /// "address": "192.168.2.1", /// "b": "true" /// }"#).unwrap(); /// assert_eq!(Ipv4Addr::new(192, 168, 2, 1), v.address); /// assert!(v.b); /// /// let x = A { /// address: Ipv4Addr::new(127, 53, 0, 1), /// b: false, /// }; /// assert_eq!(r#"{"address":"127.53.0.1","b":"false"}"#, serde_json::to_string(&x).unwrap()); /// # } /// ``` pub mod display_fromstr { use super::*; use std::str::FromStr; /// Deserialize T using [FromStr] pub fn deserialize<'de, D, T>(deserializer: D) -> Result<T, D::Error> where D: Deserializer<'de>, T: FromStr, T::Err: Display, { struct Helper<S>(PhantomData<S>); impl<'de, S> Visitor<'de> for Helper<S> where S: FromStr, <S as FromStr>::Err: Display, { type Value = S; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { write!(formatter, "valid json object") } fn visit_str<E>(self, value: &str) -> Result<Self::Value, E> where E: Error, { value.parse::<Self::Value>().map_err(Error::custom) } } deserializer.deserialize_str(Helper(PhantomData)) } /// Serialize T using [Display] pub fn serialize<T, S>(value: &T, serializer: S) -> Result<S::Ok, S::Error> where T: Display, S: Serializer, { serializer.serialize_str(&*value.to_string()) } } /// De/Serialize sequences using [FromIterator] and [IntoIterator] implementation for it and [Display][] and [FromStr][] implementation for each element /// /// This allows to serialize and deserialize collections with elements which can be represented as strings. /// /// [FromIterator]: https://doc.rust-lang.org/std/iter/trait.FromIterator.html /// [IntoIterator]: https://doc.rust-lang.org/std/iter/trait.IntoIterator.html /// [Display]: https://doc.rust-lang.org/stable/std/fmt/trait.Display.html /// [FromStr]: https://doc.rust-lang.org/stable/std/str/trait.FromStr.html /// /// # Examples /// /// ``` /// # extern crate serde; /// # #[macro_use] /// # extern crate serde_derive; /// # extern crate serde_json; /// # extern crate serde_with; /// # use std::net::Ipv4Addr; /// # use std::collections::BTreeSet; /// #[derive(Deserialize, Serialize)] /// struct A { /// #[serde(with = "serde_with::rust::seq_display_fromstr")] /// addresses: BTreeSet<Ipv4Addr>, /// #[serde(with = "serde_with::rust::seq_display_fromstr")] /// bs: Vec<bool>, /// } /// /// # fn main() { /// let v: A = serde_json::from_str(r#"{ /// "addresses": ["192.168.2.1", "192.168.2.2", "192.168.1.1", "192.168.2.2"], /// "bs": ["true", "false"] /// }"#).unwrap(); /// assert_eq!(v.addresses.len(), 3); /// assert!(v.addresses.contains(&Ipv4Addr::new(192, 168, 2, 1))); /// assert!(v.addresses.contains(&Ipv4Addr::new(192, 168, 2, 2))); /// assert!(!v.addresses.contains(&Ipv4Addr::new(192, 168, 1, 2))); /// assert_eq!(v.bs.len(), 2); /// assert!(v.bs[0]); /// assert!(!v.bs[1]); /// /// let x = A { /// addresses: vec![ /// Ipv4Addr::new(127, 53, 0, 1), /// Ipv4Addr::new(127, 53, 1, 1), /// Ipv4Addr::new(127, 53, 0, 2) /// ].into_iter().collect(), /// bs: vec![false, true], /// }; /// assert_eq!(r#"{"addresses":["127.53.0.1","127.53.0.2","127.53.1.1"],"bs":["false","true"]}"#, serde_json::to_string(&x).unwrap()); /// # } /// ``` pub mod seq_display_fromstr { use serde::{ de::{Deserializer, Error, SeqAccess, Visitor}, ser::{SerializeSeq, Serializer}, }; use std::{ fmt::{self, Display}, iter::{FromIterator, IntoIterator}, marker::PhantomData, str::FromStr, }; /// Deserialize collection T using [FromIterator] and [FromStr] for each element pub fn deserialize<'de, D, T, I>(deserializer: D) -> Result<T, D::Error> where D: Deserializer<'de>, T: FromIterator<I> + Sized, I: FromStr, I::Err: Display, { struct Helper<S>(PhantomData<S>); impl<'de, S> Visitor<'de> for Helper<S> where S: FromStr, <S as FromStr>::Err: Display, { type Value = Vec<S>; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { write!(formatter, "a sequence") } fn visit_seq<A>(self, mut access: A) -> Result<Self::Value, A::Error> where A: SeqAccess<'de>, { let mut values = access .size_hint() .map(Self::Value::with_capacity) .unwrap_or_else(Self::Value::new); while let Some(value) = access.next_element::<&str>()? { values.push(value.parse::<S>().map_err(Error::custom)?); } Ok(values) } } deserializer .deserialize_seq(Helper(PhantomData)) .map(T::from_iter) } /// Serialize collection T using [IntoIterator] and [Display] for each element pub fn serialize<S, T, I>(value: &T, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer, for<'a> &'a T: IntoIterator<Item = &'a I>, I: Display, { let iter = value.into_iter(); let (_, to) = iter.size_hint(); let mut seq = serializer.serialize_seq(to)?; for item in iter { seq.serialize_element(&item.to_string())?; } seq.end() } } /// De/Serialize a delimited collection using [Display][] and [FromStr][] implementation /// /// You can define an arbitrary separator, by specifying a type which implements [Separator][]. /// Some common ones, like space and comma are already predefined and you can find them [here][Separator]. /// /// An empty string deserializes as an empty collection. /// /// [Display]: https://doc.rust-lang.org/stable/std/fmt/trait.Display.html /// [FromStr]: https://doc.rust-lang.org/stable/std/str/trait.FromStr.html /// [Separator]: ../trait.Separator.html /// /// # Examples /// /// ``` /// # extern crate serde; /// # #[macro_use] /// # extern crate serde_derive; /// # extern crate serde_json; /// # extern crate serde_with; /// use serde_with::{CommaSeparator, SpaceSeparator}; /// use std::collections::BTreeSet; /// /// #[derive(Deserialize, Serialize)] /// struct A { /// #[serde(with = "serde_with::rust::StringWithSeparator::<SpaceSeparator>")] /// tags: Vec<String>, /// #[serde(with = "serde_with::rust::StringWithSeparator::<CommaSeparator>")] /// more_tags: BTreeSet<String>, /// } /// /// # fn main() { /// let v: A = serde_json::from_str(r##"{ /// "tags": "#hello #world", /// "more_tags": "foo,bar,bar" /// }"##).unwrap(); /// assert_eq!(vec!["#hello", "#world"], v.tags); /// assert_eq!(2, v.more_tags.len()); /// /// let x = A { /// tags: vec!["1".to_string(), "2".to_string(), "3".to_string()], /// more_tags: BTreeSet::new(), /// }; /// assert_eq!(r#"{"tags":"1 2 3","more_tags":""}"#, serde_json::to_string(&x).unwrap()); /// # } /// ``` #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Default)] pub struct StringWithSeparator<Sep>(PhantomData<Sep>); impl<Sep> StringWithSeparator<Sep> where Sep: Separator, { /// Serialize collection into a string with separator symbol pub fn serialize<S, T, V>(values: T, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer, T: IntoIterator<Item = V>, V: Display, { let mut s = String::new(); for v in values { s.push_str(&*v.to_string()); s.push_str(Sep::separator()); } serializer.serialize_str(if !s.is_empty() { // remove trailing separator if present &s[..s.len() - Sep::separator().len()] } else { &s[..] }) } /// Deserialize a collection from a string with separator symbol pub fn deserialize<'de, D, T, V>(deserializer: D) -> Result<T, D::Error> where D: Deserializer<'de>, T: FromIterator<V>, V: FromStr, V::Err: Display, { let s = String::deserialize(deserializer)?; if s.is_empty() { Ok(None.into_iter().collect()) } else { s.split(Sep::separator()) .map(FromStr::from_str) .collect::<Result<_, _>>() .map_err(Error::custom) } } } /// Makes a distinction between a missing, unset, or existing value /// /// Some serialization formats make a distinction between missing fields, fields with a `null` /// value, and existing values. One such format is JSON. By default it is not easily possible to /// differentiate between a missing value and a field which is `null`, as they deserialize to the /// same value. This helper changes it, by using an `Option<Option<T>>` to deserialize into. /// /// * `None`: Represents a missing value. /// * `Some(None)`: Represents a `null` value. /// * `Some(Some(value))`: Represents an existing value. /// /// # Examples /// /// ```rust /// # extern crate serde; /// # #[macro_use] /// # extern crate serde_derive; /// # extern crate serde_json; /// # extern crate serde_with; /// # #[derive(Debug, PartialEq, Eq)] /// #[derive(Deserialize, Serialize)] /// struct Doc { /// #[serde( /// default, // <- important for deserialization /// skip_serializing_if = "Option::is_none", // <- important for serialization /// with = "::serde_with::rust::double_option", /// )] /// a: Option<Option<u8>>, /// } /// # fn main() { /// // Missing Value /// let s = r#"{}"#; /// assert_eq!(Doc {a: None}, serde_json::from_str(s).unwrap()); /// assert_eq!(s, serde_json::to_string(&Doc {a: None}).unwrap()); /// /// // Unset Value /// let s = r#"{"a":null}"#; /// assert_eq!(Doc {a: Some(None)}, serde_json::from_str(s).unwrap()); /// assert_eq!(s, serde_json::to_string(&Doc {a: Some(None)}).unwrap()); /// /// // Existing Value /// let s = r#"{"a":5}"#; /// assert_eq!(Doc {a: Some(Some(5))}, serde_json::from_str(s).unwrap()); /// assert_eq!(s, serde_json::to_string(&Doc {a: Some(Some(5))}).unwrap()); /// # } /// ``` #[cfg_attr(feature = "cargo-clippy", allow(option_option))] pub mod double_option { use super::*; /// Deserialize potentially non-existing optional value pub fn deserialize<'de, T, D>(deserializer: D) -> Result<Option<Option<T>>, D::Error> where T: Deserialize<'de>, D: Deserializer<'de>, { Deserialize::deserialize(deserializer).map(Some) } /// Serialize optional value pub fn serialize<S, T>(values: &Option<Option<T>>, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer, T: Serialize, { match values { None => serializer.serialize_unit(), Some(None) => serializer.serialize_none(), Some(Some(v)) => serializer.serialize_some(&v), } } } /// Serialize inner value if `Some(T)`. If `None`, serialize the unit struct `()`. /// /// When used in conjunction with `skip_serializing_if = "Option::is_none"` and /// `default`, you can build an optional value by skipping if it is `None`, or serializing its /// inner value if `Some(T)`. /// /// Not all serialization formats easily support optional values. /// While JSON uses the `Option` type to represent optional values and only serializes the inner /// part of the `Some()`, other serialization formats, such as [RON][], choose to serialize the /// `Some` around a value. /// This helper helps building a truly optional value for such serializers. /// /// [RON]: https://github.com/ron-rs/ron /// /// # Example /// /// ```rust /// # extern crate serde; /// # #[macro_use] /// # extern crate serde_derive; /// # extern crate serde_json; /// # extern crate serde_with; /// # extern crate ron; /// # #[derive(Debug, Eq, PartialEq)] /// #[derive(Deserialize, Serialize)] /// struct Doc { /// mandatory: usize, /// #[serde( /// default, // <- important for deserialization /// skip_serializing_if = "Option::is_none", // <- important for serialization /// with = "::serde_with::rust::unwrap_or_skip", /// )] /// optional: Option<usize>, /// } /// # fn main() { /// /// // Transparently add/remove Some() wrapper /// # let pretty_config = ron::ser::PrettyConfig::default(); /// let s = r#"( /// mandatory: 1, /// optional: 2, /// )"#; /// let v = Doc { /// mandatory: 1, /// optional: Some(2), /// }; /// assert_eq!(v, ron::de::from_str(s).unwrap()); /// assert_eq!(s, ron::ser::to_string_pretty(&v, pretty_config).unwrap()); /// /// // Missing values are deserialized as `None` /// // while `None` values are skipped during serialization. /// # let pretty_config = ron::ser::PrettyConfig::default(); /// let s = r#"( /// mandatory: 1, /// )"#; /// let v = Doc { /// mandatory: 1, /// optional: None, /// }; /// assert_eq!(v, ron::de::from_str(s).unwrap()); /// assert_eq!(s, ron::ser::to_string_pretty(&v, pretty_config).unwrap()); /// # } /// ``` pub mod unwrap_or_skip { use super::*; /// Deserialize value wrapped in Some(T) pub fn deserialize<'de, D, T>(deserializer: D) -> Result<Option<T>, D::Error> where D: Deserializer<'de>, T: DeserializeOwned, { T::deserialize(deserializer).map(Some) } /// Serialize value if Some(T), unit struct if None pub fn serialize<T, S>(option: &Option<T>, serializer: S) -> Result<S::Ok, S::Error> where T: Serialize, S: Serializer, { if let Some(value) = option { value.serialize(serializer) } else { ().serialize(serializer) } } } /// Ensure no duplicate values exist in a set. /// /// By default serde has a last-value-wins implementation, if duplicate values for a set exist. /// Sometimes it is desirable to know when such an event happens, as the first value is overwritten /// and it can indicate an error in the serialized data. /// /// This helper returns an error if two identical values exist in a set. /// /// # Example /// /// ```rust /// # extern crate serde; /// # #[macro_use] /// # extern crate serde_derive; /// # extern crate serde_json; /// # extern crate serde_with; /// # use std::{collections::HashSet, iter::FromIterator}; /// # #[derive(Debug, Eq, PartialEq)] /// #[derive(Deserialize)] /// struct Doc { /// #[serde(with = "::serde_with::rust::sets_duplicate_value_is_error")] /// set: HashSet<usize>, /// } /// # fn main() { /// /// // Sets are serialized normally, /// let s = r#"{"set": [1, 2, 3, 4]}"#; /// let v = Doc { /// set: HashSet::from_iter(vec![1, 2, 3, 4]), /// }; /// assert_eq!(v, serde_json::from_str(s).unwrap()); /// /// // but create an error if duplicate values, like the `1`, exist. /// let s = r#"{"set": [1, 2, 3, 4, 1]}"#; /// let res: Result<Doc, _> = serde_json::from_str(s); /// assert!(res.is_err()); /// # } /// ``` pub mod sets_duplicate_value_is_error { use super::*; use duplicate_key_impls::PreventDuplicateInsertsSet; /// Deserialize a set and return an error on duplicate values pub fn deserialize<'de, D, T, V>(deserializer: D) -> Result<T, D::Error> where T: PreventDuplicateInsertsSet<V>, V: Deserialize<'de>, D: Deserializer<'de>, { struct SeqVisitor<T, V> { marker: PhantomData<T>, set_item_type: PhantomData<V>, }; impl<'de, T, V> Visitor<'de> for SeqVisitor<T, V> where T: PreventDuplicateInsertsSet<V>, V: Deserialize<'de>, { type Value = T; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { formatter.write_str("a sequence") } #[inline] fn visit_seq<A>(self, mut access: A) -> Result<Self::Value, A::Error> where A: SeqAccess<'de>, { let mut values = Self::Value::new(access.size_hint()); while let Some(value) = access.next_element()? { if !values.insert(value) { return Err(Error::custom("invalid entry: found duplicate value")); }; } Ok(values) } } let visitor = SeqVisitor { marker: PhantomData, set_item_type: PhantomData, }; deserializer.deserialize_seq(visitor) } } /// Ensure no duplicate keys exist in a map. /// /// By default serde has a last-value-wins implementation, if duplicate keys for a map exist. /// Sometimes it is desirable to know when such an event happens, as the first value is overwritten /// and it can indicate an error in the serialized data. /// /// This helper returns an error if two identical keys exist in a map. /// /// # Example /// /// ```rust /// # extern crate serde; /// # #[macro_use] /// # extern crate serde_derive; /// # extern crate serde_json; /// # extern crate serde_with; /// # use std::collections::HashMap; /// # #[derive(Debug, Eq, PartialEq)] /// #[derive(Deserialize)] /// struct Doc { /// #[serde(with = "::serde_with::rust::maps_duplicate_key_is_error")] /// map: HashMap<usize, usize>, /// } /// # fn main() { /// /// // Maps are serialized normally, /// let s = r#"{"map": {"1": 1, "2": 2, "3": 3}}"#; /// let mut v = Doc { /// map: HashMap::new(), /// }; /// v.map.insert(1, 1); /// v.map.insert(2, 2); /// v.map.insert(3, 3); /// assert_eq!(v, serde_json::from_str(s).unwrap()); /// /// // but create an error if duplicate keys, like the `1`, exist. /// let s = r#"{"map": {"1": 1, "2": 2, "1": 3}}"#; /// let res: Result<Doc, _> = serde_json::from_str(s); /// assert!(res.is_err()); /// # } /// ``` pub mod maps_duplicate_key_is_error { use super::*; use duplicate_key_impls::PreventDuplicateInsertsMap; /// Deserialize a map and return an error on duplicate keys pub fn deserialize<'de, D, T, K, V>(deserializer: D) -> Result<T, D::Error> where T: PreventDuplicateInsertsMap<K, V>, K: Deserialize<'de>, V: Deserialize<'de>, D: Deserializer<'de>, { struct MapVisitor<T, K, V> { marker: PhantomData<T>, map_key_type: PhantomData<K>, map_value_type: PhantomData<V>, }; impl<'de, T, K, V> Visitor<'de> for MapVisitor<T, K, V> where T: PreventDuplicateInsertsMap<K, V>, K: Deserialize<'de>, V: Deserialize<'de>, { type Value = T; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { formatter.write_str("a map") } #[inline] fn visit_map<A>(self, mut access: A) -> Result<Self::Value, A::Error> where A: MapAccess<'de>, { let mut values = Self::Value::new(access.size_hint()); while let Some((key, value)) = access.next_entry()? { if !values.insert(key, value) { return Err(Error::custom("invalid entry: found duplicate key")); }; } Ok(values) } } let visitor = MapVisitor { marker: PhantomData, map_key_type: PhantomData, map_value_type: PhantomData, }; deserializer.deserialize_map(visitor) } } /// Ensure that the first value is taken, if duplicate values exist /// /// By default serde has a last-value-wins implementation, if duplicate keys for a set exist. /// Sometimes the opposite strategy is desired. This helper implements a first-value-wins strategy. pub mod sets_first_value_wins { use super::*; use duplicate_key_impls::DuplicateInsertsFirstWinsSet; /// Deserialize a set and return an error on duplicate values pub fn deserialize<'de, D, T, V>(deserializer: D) -> Result<T, D::Error> where T: DuplicateInsertsFirstWinsSet<V>, V: Deserialize<'de>, D: Deserializer<'de>, { struct SeqVisitor<T, V> { marker: PhantomData<T>, set_item_type: PhantomData<V>, }; impl<'de, T, V> Visitor<'de> for SeqVisitor<T, V> where T: DuplicateInsertsFirstWinsSet<V>, V: Deserialize<'de>, { type Value = T; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { formatter.write_str("a sequence") } #[inline] fn visit_seq<A>(self, mut access: A) -> Result<Self::Value, A::Error> where A: SeqAccess<'de>, { let mut values = Self::Value::new(access.size_hint()); while let Some(value) = access.next_element()? { values.insert(value); } Ok(values) } } let visitor = SeqVisitor { marker: PhantomData, set_item_type: PhantomData, }; deserializer.deserialize_seq(visitor) } } /// Ensure that the first key is taken, if duplicate keys exist /// /// By default serde has a last-key-wins implementation, if duplicate keys for a map exist. /// Sometimes the opposite strategy is desired. This helper implements a first-key-wins strategy. /// /// # Example /// /// ```rust /// # extern crate serde; /// # #[macro_use] /// # extern crate serde_derive; /// # extern crate serde_json; /// # extern crate serde_with; /// # use std::collections::HashMap; /// # #[derive(Debug, Eq, PartialEq)] /// #[derive(Deserialize)] /// struct Doc { /// #[serde(with = "::serde_with::rust::maps_first_key_wins")] /// map: HashMap<usize, usize>, /// } /// # fn main() { /// /// // Maps are serialized normally, /// let s = r#"{"map": {"1": 1, "2": 2, "3": 3}}"#; /// let mut v = Doc { /// map: HashMap::new(), /// }; /// v.map.insert(1, 1); /// v.map.insert(2, 2); /// v.map.insert(3, 3); /// assert_eq!(v, serde_json::from_str(s).unwrap()); /// /// // but create an error if duplicate keys, like the `1`, exist. /// let s = r#"{"map": {"1": 1, "2": 2, "1": 3}}"#; /// let mut v = Doc { /// map: HashMap::new(), /// }; /// v.map.insert(1, 1); /// v.map.insert(2, 2); /// assert_eq!(v, serde_json::from_str(s).unwrap()); /// # } /// ``` pub mod maps_first_key_wins { use super::*; use duplicate_key_impls::DuplicateInsertsFirstWinsMap; /// Deserialize a map and return an error on duplicate keys pub fn deserialize<'de, D, T, K, V>(deserializer: D) -> Result<T, D::Error> where T: DuplicateInsertsFirstWinsMap<K, V>, K: Deserialize<'de>, V: Deserialize<'de>, D: Deserializer<'de>, { struct MapVisitor<T, K, V> { marker: PhantomData<T>, map_key_type: PhantomData<K>, map_value_type: PhantomData<V>, }; impl<'de, T, K, V> Visitor<'de> for MapVisitor<T, K, V> where T: DuplicateInsertsFirstWinsMap<K, V>, K: Deserialize<'de>, V: Deserialize<'de>, { type Value = T; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { formatter.write_str("a map") } #[inline] fn visit_map<A>(self, mut access: A) -> Result<Self::Value, A::Error> where A: MapAccess<'de>, { let mut values = Self::Value::new(access.size_hint()); while let Some((key, value)) = access.next_entry()? { values.insert(key, value); } Ok(values) } } let visitor = MapVisitor { marker: PhantomData, map_key_type: PhantomData, map_value_type: PhantomData, }; deserializer.deserialize_map(visitor) } } /// De/Serialize a `Option<String>` type while transforming the empty string to `None` /// /// Convert an `Option<T>` from/to string using `FromStr` and `AsRef<str>` implementations. /// An empty string is deserialized as `None` and a `None` vice versa. /// /// # Examples /// /// ``` /// # extern crate serde; /// # #[macro_use] /// # extern crate serde_derive; /// # extern crate serde_json; /// # extern crate serde_with; /// /// #[derive(Deserialize, Serialize)] /// struct A { /// #[serde(with = "serde_with::rust::string_empty_as_none")] /// tags: Option<String>, /// } /// /// # fn main() { /// let v: A = serde_json::from_str(r##"{ /// "tags": "" /// }"##).unwrap(); /// assert!(v.tags.is_none()); /// /// let v: A = serde_json::from_str(r##"{ /// "tags": "Hi" /// }"##).unwrap(); /// assert_eq!(Some("Hi".to_string()), v.tags); /// /// let x = A { /// tags: Some("This is text".to_string()), /// }; /// assert_eq!(r#"{"tags":"This is text"}"#, serde_json::to_string(&x).unwrap()); /// /// let x = A { /// tags: None, /// }; /// assert_eq!(r#"{"tags":""}"#, serde_json::to_string(&x).unwrap()); /// # } /// ``` pub mod string_empty_as_none { use super::*; /// Deserialize an `Option<T>` from a string using `FromStr` pub fn deserialize<'de, D, S>(deserializer: D) -> Result<Option<S>, D::Error> where D: Deserializer<'de>, S: FromStr, S::Err: Display, { struct OptionStringEmptyNone<S>(PhantomData<S>); impl<'de, S> Visitor<'de> for OptionStringEmptyNone<S> where S: FromStr, S::Err: Display, { type Value = Option<S>; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { formatter.write_str("any string") } fn visit_str<E>(self, value: &str) -> Result<Self::Value, E> where E: Error, { match value { "" => Ok(None), v => S::from_str(v).map(Some).map_err(Error::custom), } } fn visit_string<E>(self, value: String) -> Result<Self::Value, E> where E: Error, { match &*value { "" => Ok(None), v => S::from_str(v).map(Some).map_err(Error::custom), } } // handles the `null` case fn visit_unit<E>(self) -> Result<Self::Value, E> where E: Error, { Ok(None) } } deserializer.deserialize_any(OptionStringEmptyNone(PhantomData)) } /// Serialize a string from `Option<T>` using `AsRef<str>` or using the empty string if `None`. pub fn serialize<T, S>(option: &Option<T>, serializer: S) -> Result<S::Ok, S::Error> where T: AsRef<str>, S: Serializer, { if let Some(value) = option { value.as_ref().serialize(serializer) } else { "".serialize(serializer) } } }