Model 的存储

Unlike the policy, the model can only be loaded, it cannot be saved. We believe that the model is not a dynamic component and should not be modified at runtime, so we have not implemented an API to save the model into storage.

However, there is good news. We provide three equivalent ways to load a model, either statically or dynamically:

从 .CONF 文件中加载 model

这是使用Casbin的最常见方式。 It is easy to understand for beginners and convenient for sharing when you need help from the Casbin team.

The content of the .CONF file examples/rbac_model.conf is as follows:

[request_definition]
r = sub, obj, act

[policy_definition]
p = sub, obj, act

[role_definition]
g = _, _

[policy_effect]
e = some(where (p.eft == allow))

[matchers]
m = g(r.sub, p.sub) && r.obj == p.obj && r.act == p.act

Then you can load the model file as follows:

e := casbin.NewEnforcer("examples/rbac_model.conf", "examples/rbac_policy.csv")

从代码加载 model

The model can be initialized dynamically from code instead of using a .CONF file. 以下是RBAC模式的一个示例：

import (
    "github.com/casbin/casbin/v2"
    "github.com/casbin/casbin/v2/model"
    "github.com/casbin/casbin/v2/persist/file-adapter"
)

// 从Go代码初始化模型
m := model.NewModel()
m.AddDef("r", "r", "sub, obj, act")
m.AddDef("p", "p", "sub, obj, act")
m.AddDef("g", "g", "_, _")
m.AddDef("e", "e", "some(where (p.eft == allow))")
m.AddDef("m", "m", "g(r.sub, p.sub) && r.obj == p.obj && r.act == p.act")

// 从CSV文件adapter加载策略规则
// Replace it with your adapter to avoid using files.
a := fileadapter.NewAdapter("examples/rbac_policy.csv")

// 创建enforcer
e := casbin.NewEnforcer(m, a)

从字符串加载的 model

Alternatively, you can load the entire model text from a multi-line string. The advantage of this approach is that you do not need to maintain a model file.

import (
    "github.com/casbin/casbin/v2"
    "github.com/casbin/casbin/v2/model"
)

// 从字符串初始化模型
text :=
`
[request_definition]
r = sub, obj, act

[policy_definition]
p = sub, obj, act

[role_definition]
g = _, _

[policy_effect]
e = some(where (p.eft == allow))

[matchers]
m = g(r.sub, p.sub) && r.obj == p.obj && r.act == p.act
`
m, _ := model.NewModelFromString(text)

// 从CSV文件adapter加载策略规则
// Replace it with your adapter to avoid using files.
a := fileadapter.NewAdapter("examples/rbac_policy.csv")

// 创建enforcer
e := casbin.NewEnforcer(m, a)