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named_template.go
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/
named_template.go
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package sqlnt
import (
"context"
"database/sql"
"fmt"
)
// NamedTemplate represents a named template
//
// Use NewNamedTemplate or MustCreateNamedTemplate to create a new one
type NamedTemplate interface {
// Statement returns the sql statement to use (with named args transposed)
Statement() string
// StatementAndArgs returns the sql statement to use (with named args transposed) and
// the input named args converted to positional args
//
// Essentially the same as calling Statement and then Args
StatementAndArgs(args ...any) (string, []any, error)
// MustStatementAndArgs is the same as StatementAndArgs, except no error is returned (and panics on error)
MustStatementAndArgs(args ...any) (string, []any)
// OriginalStatement returns the original named template statement
OriginalStatement() string
// Args converts the input named args to positional args (for use in db.Exec, db.Query etc.)
//
// Each arg in the supplied args can be:
//
// * map[string]any
//
// * sql.NamedArg
//
// * or any map where all keys are set as string
//
// * or anything that can be marshalled and then unmarshalled to map[string]any (such as structs!)
//
// If any of the named args specified in the query are missing, returns an error
//
// NB. named args are not considered missing when they have denoted as omissible (see NamedTemplate.OmissibleArgs) or
// have been set with a default value (see NamedTemplate.DefaultValue)
Args(args ...any) ([]any, error)
// MustArgs is the same as Args, except no error is returned (and panics on error)
MustArgs(args ...any) []any
// ArgsCount returns the number of args that are passed into the statement
ArgsCount() int
// OmissibleArgs specifies the names of args that can be omitted
//
// Calling this without any names makes all args omissible
//
// Note: Named args can also be set as omissible in the template - example:
// tmp := sqlnt.MustCreateNamedTemplate(`INSERT INTO table (col_a,col_b) VALUES (:a, :b?)`)
// makes the named arg "b" omissible (denoted by the '?' after name)
OmissibleArgs(names ...string) NamedTemplate
// DefaultValue specifies a value to be used for a given arg name when the arg
// is not supplied in the map for Args or MustArgs
//
// Setting a default value for an arg name also makes that arg omissible
//
// If the value passed is a
// func(name string) any
// then that func is called to obtain the default value
DefaultValue(name string, v any) NamedTemplate
// NullableStringArgs specifies the names of args that are nullable string
// i.e. where the value is an empty string, null is used instead
NullableStringArgs(names ...string) NamedTemplate
// GetArgNames returns a map of the arg names (where the map value is a bool indicating whether
// the arg is omissible
//
// NB. Each arg is immutable - changing it has no effect on the template
GetArgNames() map[string]bool
// GetArgsInfo returns a map of each named arg info
//
// NB. Each arg info is immutable - changing it has no effect on the template
GetArgsInfo() map[string]ArgInfo
// Clone clones the named template to another with a different option
Clone(option Option) NamedTemplate
// Append appends a statement portion to current statement and returns a new NamedTemplate
//
// Returns an error if the supplied statement portion cannot be parsed for arg names
Append(portion string) (NamedTemplate, error)
// MustAppend is the same as Append, except no error is returned (and panics on error)
MustAppend(portion string) NamedTemplate
// Exec performs sql.DB.Exec on the supplied db with the supplied named args
Exec(db *sql.DB, args ...any) (sql.Result, error)
// ExecContext performs sql.DB.ExecContext on the supplied db with the supplied named args
ExecContext(ctx context.Context, db *sql.DB, args ...any) (sql.Result, error)
// Query performs sql.DB.Query on the supplied db with the supplied named args
Query(db *sql.DB, args ...any) (*sql.Rows, error)
// QueryContext performs sql.DB.QueryContext on the supplied db with the supplied named args
QueryContext(ctx context.Context, db *sql.DB, args ...any) (*sql.Rows, error)
}
type namedTemplate struct {
originalStatement string
statement string
args map[string]*namedArg
argsCount int
usePositionalTags bool
argTag string
tokenOptions []TokenOption
}
// NewNamedTemplate creates a new NamedTemplate
//
// # Returns an error if the supplied template cannot be parsed for arg names
//
// Multiple options can be specified - each must be either a sqlnt.Option or sqlnt.TokenOption
func NewNamedTemplate(statement string, options ...any) (NamedTemplate, error) {
opt, tokenOptions, err := getOptions(options...)
if err != nil {
return nil, err
}
result := newNamedTemplate(statement, opt.UsePositionalTags(), opt.ArgTag(), tokenOptions)
if err = result.buildArgs(); err != nil {
return nil, err
}
return result, nil
}
// MustCreateNamedTemplate creates a new NamedTemplate
//
// is the same as NewNamedTemplate, except panics in case of error
func MustCreateNamedTemplate(statement string, options ...any) NamedTemplate {
nt, err := NewNamedTemplate(statement, options...)
if err != nil {
panic(err)
}
return nt
}
func newNamedTemplate(statement string, usePositionalTags bool, argTag string, tokenOptions []TokenOption) *namedTemplate {
return &namedTemplate{
originalStatement: statement,
args: map[string]*namedArg{},
usePositionalTags: usePositionalTags,
argTag: argTag,
tokenOptions: tokenOptions,
}
}
// Statement returns the sql statement to use (with named args transposed)
func (n *namedTemplate) Statement() string {
return n.statement
}
// StatementAndArgs returns the sql statement to use (with named args transposed) and
// the input named args converted to positional args
//
// Essentially the same as calling Statement and then Args
func (n *namedTemplate) StatementAndArgs(args ...any) (string, []any, error) {
rargs, err := n.Args(args...)
return n.statement, rargs, err
}
// MustStatementAndArgs is the same as StatementAndArgs, except no error is returned (and panics on error)
func (n *namedTemplate) MustStatementAndArgs(args ...any) (string, []any) {
rargs, err := n.Args(args...)
if err != nil {
panic(err)
}
return n.statement, rargs
}
// OriginalStatement returns the original named template statement
func (n *namedTemplate) OriginalStatement() string {
return n.originalStatement
}
// Args converts the input named args to positional args (for use in db.Exec, db.Query etc.)
//
// Each arg in the supplied args can be:
//
// * map[string]any
//
// * sql.NamedArg
//
// * or any map where all keys are set as string
//
// * or anything that can be marshalled and then unmarshalled to map[string]any (such as structs!)
//
// # If any of the named args specified in the query are missing, returns an error
//
// NB. named args are not considered missing when they have denoted as omissible (see NamedTemplate.OmissibleArgs) or
// have been set with a default value (see NamedTemplate.DefaultValue)
func (n *namedTemplate) Args(args ...any) ([]any, error) {
out := make([]any, n.argsCount)
mapped, err := mappedArgs(args...)
if err != nil {
return nil, err
}
for name, arg := range n.args {
if v, ok := mapped[name]; ok {
av := arg.value(v)
for _, posn := range arg.positions {
out[posn] = av
}
} else if !arg.omissible {
return nil, fmt.Errorf("named arg '%s' missing", name)
} else if arg.defValue != nil {
v = arg.defaultedValue(name)
for _, posn := range arg.positions {
out[posn] = v
}
}
}
return out, nil
}
// MustArgs is the same as Args, except no error is returned (and panics on error)
func (n *namedTemplate) MustArgs(args ...any) []any {
out, err := n.Args(args...)
if err != nil {
panic(err)
}
return out
}
// ArgsCount returns the number of args that are passed into the statement
func (n *namedTemplate) ArgsCount() int {
return n.argsCount
}
// OmissibleArgs specifies the names of args that can be omitted
//
// # Calling this without any names makes all args omissible
//
// Note: Named args can also be set as omissible in the template - example:
//
// tmp := sqlnt.MustCreateNamedTemplate(`INSERT INTO table (col_a,col_b) VALUES (:a, :b?)`)
//
// makes the named arg "b" omissible (denoted by the '?' after name)
func (n *namedTemplate) OmissibleArgs(names ...string) NamedTemplate {
if len(names) == 0 {
for _, arg := range n.args {
arg.omissible = true
}
} else {
for _, name := range names {
if arg, ok := n.args[name]; ok {
arg.omissible = true
}
}
}
return n
}
// DefaultValueFunc is the function signature for funcs that can be passed to
// NamedTemplate.DefaultValue
type DefaultValueFunc func(name string) any
// DefaultValue specifies a value to be used for a given arg name when the arg
// is not supplied in the map for Args or MustArgs
//
// # Setting a default value for an arg name also makes that arg omissible
//
// If the value passed is a
//
// func(name string) any
//
// then that func is called to obtain the default value
func (n *namedTemplate) DefaultValue(name string, v interface{}) NamedTemplate {
if arg, ok := n.args[name]; ok {
arg.omissible = true
if dvf, ok := v.(func(name string) any); ok {
arg.defValue = dvf
} else {
arg.defValue = func(name string) any {
return v
}
}
}
return n
}
// NullableStringArgs specifies the names of args that are nullable string
// i.e. where the value is an empty string, null is used instead
func (n *namedTemplate) NullableStringArgs(names ...string) NamedTemplate {
for _, name := range names {
if arg, ok := n.args[name]; ok {
arg.nullableString = true
}
}
return n
}
// GetArgNames returns a map of the arg names (where the map value is a bool indicating whether
// the arg is omissible
func (n *namedTemplate) GetArgNames() map[string]bool {
result := make(map[string]bool, len(n.args))
for name, arg := range n.args {
result[name] = arg.omissible
}
return result
}
// GetArgsInfo returns a map of each named arg info
//
// NB. Each arg info is immutable - changing it has no effect on the template
func (n *namedTemplate) GetArgsInfo() map[string]ArgInfo {
result := make(map[string]ArgInfo, len(n.args))
for name, arg := range n.args {
result[name] = arg.toInfo()
}
return result
}
// Clone clones the named template to another with a different option
func (n *namedTemplate) Clone(option Option) NamedTemplate {
if option == nil {
option = DefaultsOption
}
if option.UsePositionalTags() == n.usePositionalTags && option.ArgTag() == n.argTag {
// no material change, just copy everything...
return n.copy()
} else {
r := newNamedTemplate(n.originalStatement, option.UsePositionalTags(), option.ArgTag(), n.tokenOptions)
_ = r.buildArgs()
for name, arg := range n.args {
arg.copyOptionsTo(r.args[name])
}
return r
}
}
// Append appends a statement portion to current statement and returns a new NamedTemplate
//
// Returns an error if the supplied statement portion cannot be parsed for arg names
func (n *namedTemplate) Append(portion string) (NamedTemplate, error) {
result := newNamedTemplate(n.originalStatement+portion, n.usePositionalTags, n.argTag, n.tokenOptions)
if err := result.buildArgs(); err != nil {
return nil, err
}
for name, arg := range n.args {
if rarg, ok := result.args[name]; ok {
rarg.omissible = arg.omissible
rarg.defValue = arg.defValue
}
}
return result, nil
}
// MustAppend is the same as Append, except no error is returned (and panics on error)
func (n *namedTemplate) MustAppend(portion string) NamedTemplate {
if result, err := n.Append(portion); err == nil {
return result
} else {
panic(err)
}
}
// Exec performs sql.DB.Exec on the supplied db with the supplied named args
func (n *namedTemplate) Exec(db *sql.DB, args ...any) (sql.Result, error) {
if qargs, err := n.Args(args...); err == nil {
return db.Exec(n.statement, qargs...)
} else {
return nil, err
}
}
// ExecContext performs sql.DB.ExecContext on the supplied db with the supplied named args
func (n *namedTemplate) ExecContext(ctx context.Context, db *sql.DB, args ...any) (sql.Result, error) {
if qargs, err := n.Args(args...); err == nil {
return db.ExecContext(ctx, n.statement, qargs...)
} else {
return nil, err
}
}
// Query performs sql.DB.Query on the supplied db with the supplied named args
func (n *namedTemplate) Query(db *sql.DB, args ...any) (*sql.Rows, error) {
if qargs, err := n.Args(args...); err == nil {
return db.Query(n.statement, qargs...)
} else {
return nil, err
}
}
// QueryContext performs sql.DB.QueryContext on the supplied db with the supplied named args
func (n *namedTemplate) QueryContext(ctx context.Context, db *sql.DB, args ...any) (*sql.Rows, error) {
if qargs, err := n.Args(args...); err == nil {
return db.QueryContext(ctx, n.statement, qargs...)
} else {
return nil, err
}
}