# Guide to upgrading from url 0.x to 1.x
* The fields of `Url` are now private because the `Url` constructor, parser,
and setters maintain invariants that could be violated if you were to set the fields directly.
Instead of accessing, for example, `url.scheme`, use the getter method, such as `url.scheme()`.
Instead of assigning directly to a field, for example `url.scheme = "https".to_string()`,
use the setter method, such as `url.set_scheme("https").unwrap()`.
(Some setters validate the new value and return a `Result` that must be used).
* The methods of `Url` now return `&str` instead of `String`,
thus reducing allocations and making serialization cheap.
* The `path()` method on `url::Url` instances used to return `Option<&[String]>`;
now it returns `&str`.
If you would like functionality more similar to the old behavior of `path()`,
use `path_segments()` that returns `Option<str::Split<char>>`.
Before upgrading:
```rust
let issue_list_url = Url::parse(
"https://github.com/rust-lang/rust/issues?labels=E-easy&state=open"
).unwrap();
assert_eq!(issue_list_url.path(), Some(&["rust-lang".to_string(),
"rust".to_string(),
"issues".to_string()][..]));
```
After upgrading:
```rust
let issue_list_url = Url::parse(
"https://github.com/rust-lang/rust/issues?labels=E-easy&state=open"
).unwrap();
assert_eq!(issue_list_url.path(), "/rust-lang/rust/issues");
assert_eq!(issue_list_url.path_segments().map(|c| c.collect::<Vec<_>>()),
Some(vec!["rust-lang", "rust", "issues"]));
```
* The `path_mut()` method on `url::Url` instances that allowed modification of a URL's path
has been replaced by `path_segments_mut()`.
Before upgrading:
```rust
let mut url = Url::parse("https://github.com/rust-lang/rust").unwrap();
url.path_mut().unwrap().push("issues");
```
After upgrading:
```rust
let mut url = Url::parse("https://github.com/rust-lang/rust").unwrap();
url.path_segments_mut().unwrap().push("issues");
```
* The `domain_mut()` method on `url::Url` instances that allowed modification of a URL's domain
has been replaced by `set_host()` and `set_ip_host()`.
* The `host()` method on `url::Url` instances used to return `Option<&Host>`;
now it returns `Option<Host<&str>>`.
The `serialize_host()` method that returned `Option<String>`
has been replaced by the `host_str()` method that returns `Option<&str>`.
* The `serialize()` method on `url::Url` instances that returned `String`
has been replaced by an `as_str()` method that returns `&str`.
Before upgrading:
```rust
let this_document = Url::parse("http://servo.github.io/rust-url/url/index.html").unwrap();
assert_eq!(this_document.serialize(), "http://servo.github.io/rust-url/url/index.html".to_string());
```
After upgrading:
```rust
let this_document = Url::parse("http://servo.github.io/rust-url/url/index.html").unwrap();
assert_eq!(this_document.as_str(), "http://servo.github.io/rust-url/url/index.html");
```
* `url::UrlParser` has been replaced by `url::Url::parse()` and `url::Url::join()`.
Before upgrading:
```rust
let this_document = Url::parse("http://servo.github.io/rust-url/url/index.html").unwrap();
let css_url = UrlParser::new().base_url(&this_document).parse("../main.css").unwrap();
assert_eq!(css_url.serialize(), "http://servo.github.io/rust-url/main.css".to_string());
```
After upgrading:
```rust
let this_document = Url::parse("http://servo.github.io/rust-url/url/index.html").unwrap();
let css_url = this_document.join("../main.css").unwrap();
assert_eq!(css_url.as_str(), "http://servo.github.io/rust-url/main.css");
```
* `url::parse_path()` and `url::UrlParser::parse_path()` have been removed without replacement.
As a workaround, you can give a base URL that you then ignore too `url::Url::parse()`.
Before upgrading:
```rust
let (path, query, fragment) = url::parse_path("/foo/bar/../baz?q=42").unwrap();
assert_eq!(path, vec!["foo".to_string(), "baz".to_string()]);
assert_eq!(query, Some("q=42".to_string()));
assert_eq!(fragment, None);
```
After upgrading:
```rust
let base = Url::parse("http://example.com").unwrap();
let with_path = base.join("/foo/bar/../baz?q=42").unwrap();
assert_eq!(with_path.path(), "/foo/baz");
assert_eq!(with_path.query(), Some("q=42"));
assert_eq!(with_path.fragment(), None);
```
* The `url::form_urlencoded::serialize()` method
has been replaced with the `url::form_urlencoded::Serializer` struct.
Instead of calling `serialize()` with key/value pairs,
create a new `Serializer` with a new string,
call the `extend_pairs()` method on the `Serializer` instance with the key/value pairs as the argument,
then call `finish()`.
Before upgrading:
```rust
let form = url::form_urlencoded::serialize(form.iter().map(|(k, v)| {
(&k[..], &v[..])
}));
```
After upgrading:
```rust
let form = url::form_urlencoded::Serializer::new(String::new()).extend_pairs(
form.iter().map(|(k, v)| { (&k[..], &v[..]) })
).finish();
```
* The `set_query_from_pairs()` method on `url::Url` instances that took key/value pairs
has been replaced with `query_pairs_mut()`, which allows you to modify the `url::Url`'s query pairs.
Before upgrading:
```rust
let mut url = Url::parse("https://duckduckgo.com/").unwrap();
let pairs = vec![
("q", "test"),
("ia", "images"),
];
url.set_query_from_pairs(pairs.iter().map(|&(k, v)| {
(&k[..], &v[..])
}));
```
After upgrading:
```rust
let mut url = Url::parse("https://duckduckgo.com/").unwrap();
let pairs = vec![
("q", "test"),
("ia", "images"),
];
url.query_pairs_mut().clear().extend_pairs(
pairs.iter().map(|&(k, v)| { (&k[..], &v[..]) })
);
```
* `url::SchemeData`, its variants `Relative` and `NonRelative`,
and the struct `url::RelativeSchemeData` have been removed.
Instead of matching on these variants
to determine if you have a URL in a relative scheme such as HTTP
versus a URL in a non-relative scheme as data,
use the `cannot_be_a_base()` method to determine which kind you have.
Before upgrading:
```rust
match url.scheme_data {
url::SchemeData::Relative(..) => {}
url::SchemeData::NonRelative(..) => {
return Err(human(format!("`{}` must have relative scheme \
data: {}", field, url)))
}
}
```
After upgrading:
```rust
if url.cannot_be_a_base() {
return Err(human(format!("`{}` must have relative scheme \
data: {}", field, url)))
}
```
* The functions `url::whatwg_scheme_type_mapper()`, the `SchemeType` enum,
and the `scheme_type_mapper()` method on `url::UrlParser` instances have been removed.
`SchemeType` had a method for getting the `default_port()`;
to replicate this functionality, use the method `port_or_known_default()` on `url::Url` instances.
The `port_or_default()` method on `url::Url` instances has been removed;
use `port_or_known_default()` instead.
Before upgrading:
```rust
let port = match whatwg_scheme_type_mapper(&url.scheme) {
SchemeType::Relative(port) => port,
_ => return Err(format!("Invalid special scheme: `{}`",
raw_url.scheme)),
};
```
After upgrading:
```rust
let port = match url.port_or_known_default() {
Some(port) => port,
_ => return Err(format!("Invalid special scheme: `{}`",
url.scheme())),
};
```
* The following formatting utilities have been removed without replacement;
look at their linked previous implementations
if you would like to replicate the functionality in your code:
* [`url::format::PathFormatter`](https://github.com/servo/rust-url/pull/176/commits/9e759f18726c8e1343162922b87163d4dd08fe3c#diff-0bb16ac13b75e9b568fa4aff61b0e71dL24)
* [`url::format::UserInfoFormatter`](https://github.com/servo/rust-url/pull/176/commits/9e759f18726c8e1343162922b87163d4dd08fe3c#diff-0bb16ac13b75e9b568fa4aff61b0e71dL50)
* [`url::format::UrlNoFragmentFormatter`](https://github.com/servo/rust-url/pull/176/commits/9e759f18726c8e1343162922b87163d4dd08fe3c#diff-0bb16ac13b75e9b568fa4aff61b0e71dL70)
* `url::percent_encoding::percent_decode()` used to have a return type of `Vec<u8>`;
now it returns an iterator of decoded `u8` bytes that also implements `Into<Cow<u8>>`.
Use `.into().to_owned()` to obtain a `Vec<u8>`.
(`.collect()` also works but might not be as efficient.)
* The `url::percent_encoding::EncodeSet` struct and constant instances
used with `url::percent_encoding::percent_encode()`
have been changed to structs that implement the trait `url::percent_encoding::EncodeSet`.
* `SIMPLE_ENCODE_SET`, `QUERY_ENCODE_SET`, `DEFAULT_ENCODE_SET`,
and `USERINFO_ENCODE_SET` have the same behavior.
* `USERNAME_ENCODE_SET` and `PASSWORD_ENCODE_SET` have been removed;
use `USERINFO_ENCODE_SET` instead.
* `HTTP_VALUE_ENCODE_SET` has been removed;
an implementation of it in the new types can be found [in hyper's source](
https://github.com/hyperium/hyper/blob/67436c5bf615cf5a55a71e32b788afef5985570e/src/header/parsing.rs#L131-L138)
if you need to replicate this functionality in your code.
* `FORM_URLENCODED_ENCODE_SET` has been removed;
instead, use the functionality in `url::form_urlencoded`.
* `PATH_SEGMENT_ENCODE_SET` has been added for use on '/'-separated path segments.
* `url::percent_encoding::percent_decode_to()` has been removed.
Use `url::percent_encoding::percent_decode()` which returns an iterator.
You can then use the iterator’s `collect()` method
or give it to some data structure’s `extend()` method.
* A number of `ParseError` variants have changed.
[See the documentation for the current set](http://servo.github.io/rust-url/url/enum.ParseError.html).
* `url::OpaqueOrigin::new()` and `url::Origin::UID(OpaqueOrigin)`
have been replaced by `url::Origin::new_opaque()` and `url::Origin::Opaque(OpaqueOrigin)`, respectively.