INI [](https://travis-ci.org/go-ini/ini) [](https://sourcegraph.com/github.com/go-ini/ini?badge)
A **Data Source** is either raw data in type `[]byte`, a file name with type `string` or `io.ReadCloser`. You can load **as many data sources as you want**. Passing other types will simply return an error.
When you cannot decide how many data sources to load at the beginning, you will still be able to **Append()** them later.
```go
err := cfg.Append("other file", []byte("other raw data"))
```
If you have a list of files with possibilities that some of them may not available at the time, and you don't know exactly which ones, you can use `LooseLoad` to ignore nonexistent files without returning error.
What happens when the section somehow does not exist? Don't panic, it automatically creates and returns a new section to you.
To create a new section:
```go
err := cfg.NewSection("new section")
```
To get a list of sections or section names:
```go
sections := cfg.Sections()
names := cfg.SectionStrings()
```
### Working with keys
To get a key under a section:
```go
key, err := cfg.Section("").GetKey("key name")
```
Same rule applies to key operations:
```go
key := cfg.Section("").Key("key name")
```
To check if a key exists:
```go
yes := cfg.Section("").HasKey("key name")
```
To create a new key:
```go
err := cfg.Section("").NewKey("name", "value")
```
To get a list of keys or key names:
```go
keys := cfg.Section("").Keys()
names := cfg.Section("").KeyStrings()
```
To get a clone hash of keys and corresponding values:
```go
hash := cfg.Section("").KeysHash()
```
### Working with values
To get a string value:
```go
val := cfg.Section("").Key("key name").String()
```
To validate key value on the fly:
```go
val := cfg.Section("").Key("key name").Validate(func(in string) string {
if len(in) == 0 {
return "default"
}
return in
})
```
If you do not want any auto-transformation (such as recursive read) for the values, you can get raw value directly (this way you get much better performance):
```go
val := cfg.Section("").Key("key name").Value()
```
To check if raw value exists:
```go
yes := cfg.Section("").HasValue("test value")
```
To get value with types:
```go
// For boolean values:
// true when value is: 1, t, T, TRUE, true, True, YES, yes, Yes, y, ON, on, On
// false when value is: 0, f, F, FALSE, false, False, NO, no, No, n, OFF, off, Off
Finally, it's time to save your configuration to somewhere.
A typical way to save configuration is writing it to a file:
```go
// ...
err = cfg.SaveTo("my.ini")
err = cfg.SaveToIndent("my.ini", "\t")
```
Another way to save is writing to a `io.Writer` interface:
```go
// ...
cfg.WriteTo(writer)
cfg.WriteToIndent(writer, "\t")
```
By default, spaces are used to align "=" sign between key and values, to disable that:
```go
ini.PrettyFormat = false
```
## Advanced Usage
### Recursive Values
For all value of keys, there is a special syntax `%(<name>)s`, where `<name>` is the key name in same section or default section, and `%(<name>)s` will be replaced by corresponding value(empty string if key not found). You can use this syntax at most 99 level of recursions.
You can use `.` in section name to indicate parent-child relationship between two or more sections. If the key not found in the child section, library will try again on its parent section until there is no parent section.
If key name is `-` in data source, then it would be seen as special syntax for auto-increment key name start from 1, and every section is independent on counter.
```ini
[features]
-: Support read/write comments of keys and sections
-: Support auto-increment of key names
-: Support load multiple files to overwrite key values
To save your time and make your code cleaner, this library supports [`NameMapper`](https://gowalker.org/gopkg.in/ini.v1#NameMapper) between struct field and actual section and key name.
There are 2 built-in name mappers:
-`AllCapsUnderscore`: it converts to format `ALL_CAPS_UNDERSCORE` then match section or key.
-`TitleUnderscore`: it converts to format `title_underscore` then match section or key.
- [File An Issue](https://github.com/go-ini/ini/issues/new)
## FAQs
### What does `BlockMode` field do?
By default, library lets you read and write values so we need a locker to make sure your data is safe. But in cases that you are very sure about only reading data through the library, you can set `cfg.BlockMode = false` to speed up read operations about **50-70%** faster.
### Why another INI library?
Many people are using my another INI library [goconfig](https://github.com/Unknwon/goconfig), so the reason for this one is I would like to make more Go style code. Also when you set `cfg.BlockMode = false`, this one is about **10-30%** faster.
To make those changes I have to confirm API broken, so it's safer to keep it in another place and start using `gopkg.in` to version my package at this time.(PS: shorter import path)
## License
This project is under Apache v2 License. See the [LICENSE](LICENSE) file for the full license text.
