| 1 | // Package idear is the roster for a Rastrillo instance: who is in it, |
| 2 | // at what role, and who may change that. It never mints a session, |
| 3 | // hashes a password, or renders a sign-in form — it sits on top of |
| 4 | // sessions and whichever identity plugin the app already chose. |
| 5 | package idear |
| 6 | |
| 7 | // Role is a member's rank within one instance. It is a string, not an |
| 8 | // int, because it round-trips through form posts and database columns |
| 9 | // without a mapping table to keep in sync — but that means any string |
| 10 | // decodes without error, so every caller that receives one from outside |
| 11 | // the package (a form, a query) must run it through ParseRole rather |
| 12 | // than trust the cast. |
| 13 | type Role string |
| 14 | |
| 15 | const ( |
| 16 | RoleOwner Role = "owner" |
| 17 | RoleAdmin Role = "admin" |
| 18 | RoleMember Role = "member" |
| 19 | ) |
| 20 | |
| 21 | // rank orders the three roles for comparison; 0 means "not a role; see |
| 22 | // Valid" rather than "below Member" so it never wins a comparison it |
| 23 | // has no business winning. |
| 24 | func rank(r Role) int { |
| 25 | switch r { |
| 26 | case RoleOwner: |
| 27 | return 3 |
| 28 | case RoleAdmin: |
| 29 | return 2 |
| 30 | case RoleMember: |
| 31 | return 1 |
| 32 | default: |
| 33 | return 0 |
| 34 | } |
| 35 | } |
| 36 | |
| 37 | // Valid reports whether r is one of the three known roles. |
| 38 | func (r Role) Valid() bool { |
| 39 | return rank(r) > 0 |
| 40 | } |
| 41 | |
| 42 | // AtLeast reports whether r's rank is at or above min's. Both sides |
| 43 | // must be valid roles — an invalid r is never at least anything, not |
| 44 | // even an equally invalid min, and an invalid min is never a threshold |
| 45 | // anything can clear. Without that second half, two unknown strings |
| 46 | // would compare equal by falling through to the same rank(0), and |
| 47 | // AtLeast would call garbage "at least" garbage. |
| 48 | func (r Role) AtLeast(min Role) bool { |
| 49 | if !r.Valid() || !min.Valid() { |
| 50 | return false |
| 51 | } |
| 52 | return rank(r) >= rank(min) |
| 53 | } |
| 54 | |
| 55 | // Title is the display form of r — "Owner", "Admin", "Member" — and |
| 56 | // the empty string for anything that isn't a role, so a template that |
| 57 | // prints it renders nothing rather than a raw lowercase form value. |
| 58 | func (r Role) Title() string { |
| 59 | switch r { |
| 60 | case RoleOwner: |
| 61 | return "Owner" |
| 62 | case RoleAdmin: |
| 63 | return "Admin" |
| 64 | case RoleMember: |
| 65 | return "Member" |
| 66 | default: |
| 67 | return "" |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | // ParseRole accepts only the three known lowercase spellings. It is the |
| 72 | // one place a string from outside the package (a posted form field, a |
| 73 | // query parameter) becomes a Role; everywhere else in idear a Role is |
| 74 | // assumed already valid. |
| 75 | func ParseRole(s string) (Role, bool) { |
| 76 | r := Role(s) |
| 77 | if !r.Valid() { |
| 78 | return "", false |
| 79 | } |
| 80 | return r, true |
| 81 | } |
| 82 | |
amadan