Simplifying Go Code -

i have 2 functions shown below similar, using different functions query db. since go doesn't encourage overloaading methods, redundancy acceptable? or should refactor them 1 function? comments welcomed.

var getcustomers = func() ([]customer, error) {     return nil, nil }  var getcustomerbyid = func(int64) (*customer, error) {     return nil, nil }  func listcustomer(w http.responsewriter, r *http.request) *apperror {     cus, err := getcustomers()     if err != nil {         return &apperror{err, "no customer found", 404}     }      res, err := json.marshal(cus)      if err != nil {         return &apperror{err, "can't display record", 500}     }      fmt.fprint(w, string(res))     return nil }  func viewcustomer(w http.responsewriter, r *http.request, id int64) *apperror {     cus, err := getcustomerbyid(id)     if err != nil {         return &apperror{err, "no customer found", 404}     }      res, err := json.marshal(cus)      if err != nil {         return &apperror{err, "can't display record", 500}     }      fmt.fprint(w, string(res))     return nil } 

suggestion use -1 list customer, i'm not sure if best can be:

func viewcustomer(w http.responsewriter, r *http.request, id int64) *apperror {     var c *customer     var clist []customer     var err error      if id < 0 {         clist, err = getcustomers()         res, err := json.marshal(clist)          if err != nil {             return &apperror{err, "can't display record", 500}         }          fmt.fprint(w, string(res))         return nil     } else {         c, err = getcustomerbyid(id)         res, err := json.marshal(c)          if err != nil {             return &apperror{err, "can't display record", 500}         }          fmt.fprint(w, string(res))         return nil     } } 

since go doesn't encourage overloaading methods, redundancy acceptable? or should refactor them 1 function?

the answer question depends heavily on real code , task. if listing 1 customer different listing several customers (that is, need different information , have different presentation logic), i'd duplication here not bad, since difference may grow larger in future, dry solution turn if , switch mess quickly. (i've had similar experience on non-go project , since think dry should not fanatic it.)

on other hand, if you're making, json api, make more dry. define getcustomers function this:

func customers(ids ...int64) ([]customer, error) { /* ... */ } 

this way can:

• call customers() , customers;
• call customers(42) , customer id 42;
• call customers(someids...) , multiple customers ids.

all can done in 1 handler in straightforward way.

all comments welcomed.

two nitpicks on code:

• getter methods in go idiomatically named foo , not getfoo, used customers in example. call db.customers(ids...), looks lot getter method.

• what's var foo = func() notation? unless there reason (like using these functions closures), i'd suggest sticking func foo() notation, since it's more idiomatic , easier grep. edit: op pointed out in comments, case var foo = func() notation of course functions can faked in testing, shown in andrew gerrand's testing techniques talk.

i hope helps.