1 files changed, 125 insertions, 0 deletions
diff --git a/server/resty/session/storage/shm.lua b/server/resty/session/storage/shm.lua
new file mode 100644
index 0000000..6f81435
--- /dev/null
+++ b/server/resty/session/storage/shm.lua
@@ -0,0 +1,125 @@
+local lock         = require "resty.lock"
+
+local setmetatable = setmetatable
+local tonumber     = tonumber
+local concat       = table.concat
+local var          = ngx.var
+local shared       = ngx.shared
+
+local function enabled(value)
+    if value == nil then return nil end
+    return value == true or (value == "1" or value == "true" or value == "on")
+end
+
+local function ifnil(value, default)
+    if value == nil then
+        return default
+    end
+
+    return enabled(value)
+end
+
+local defaults   = {
+    store        = var.session_shm_store                       or "sessions",
+    uselocking   = enabled(var.session_shm_uselocking          or true),
+    lock         = {
+        exptime  = tonumber(var.session_shm_lock_exptime,  10) or 30,
+        timeout  = tonumber(var.session_shm_lock_timeout,  10) or 5,
+        step     = tonumber(var.session_shm_lock_step,     10) or 0.001,
+        ratio    = tonumber(var.session_shm_lock_ratio,    10) or 2,
+        max_step = tonumber(var.session_shm_lock_max_step, 10) or 0.5,
+    }
+}
+
+local storage = {}
+
+storage.__index = storage
+
+function storage.new(session)
+    local config = session.shm            or defaults
+    local store  = config.store           or defaults.store
+    local locking = ifnil(config.uselocking, defaults.uselocking)
+
+    local self = {
+        store      = shared[store],
+        uselocking = locking,
+    }
+
+    if locking then
+        local lock_opts = config.lock                      or defaults.lock
+        local opts      = {
+            exptime     = tonumber(lock_opts.exptime,  10) or defaults.exptime,
+            timeout     = tonumber(lock_opts.timeout,  10) or defaults.timeout,
+            step        = tonumber(lock_opts.step,     10) or defaults.step,
+            ratio       = tonumber(lock_opts.ratio,    10) or defaults.ratio,
+            max_step    = tonumber(lock_opts.max_step, 10) or defaults.max_step,
+        }
+        self.lock = lock:new(store, opts)
+    end
+
+    return setmetatable(self, storage)
+end
+
+function storage:open(id, keep_lock)
+    if self.uselocking then
+        local ok, err = self.lock:lock(concat{ id, ".lock" })
+        if not ok then
+            return nil, err
+        end
+    end
+
+    local data, err = self.store:get(id)
+
+    if self.uselocking and (err or not data or not keep_lock) then
+        self.lock:unlock()
+    end
+
+    return data, err
+end
+
+function storage:start(id)
+    if self.uselocking then
+        return self.lock:lock(concat{ id, ".lock" })
+    end
+
+    return true
+end
+
+function storage:save(id, ttl, data, close)
+    local ok, err = self.store:set(id, data, ttl)
+    if close and self.uselocking then
+        self.lock:unlock()
+    end
+
+    return ok, err
+end
+
+function storage:close()
+    if self.uselocking then
+        self.lock:unlock()
+    end
+
+    return true
+end
+
+function storage:destroy(id)
+    self.store:delete(id)
+
+    if self.uselocking then
+        self.lock:unlock()
+    end
+
+    return true
+end
+
+function storage:ttl(id, lifetime, close)
+    local ok, err = self.store:expire(id, lifetime)
+
+    if close and self.uselocking then
+        self.lock:unlock()
+    end
+
+    return ok, err
+end
+
+return storage