forked from nytlabs/streamtools
/
getHTTP.go
113 lines (104 loc) · 2.44 KB
/
getHTTP.go
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package library
import (
"encoding/json"
"errors"
"github.com/nytlabs/gojee" // jee
"github.com/nytlabs/streamtools/st/blocks" // blocks
"github.com/nytlabs/streamtools/st/util"
"io/ioutil"
"net/http"
)
// specify those channels we're going to use to communicate with streamtools
type GetHTTP struct {
blocks.Block
queryrule chan chan interface{}
inrule chan interface{}
in chan interface{}
out chan interface{}
quit chan interface{}
}
// we need to build a simple factory so that streamtools can make new blocks of this kind
func NewGetHTTP() blocks.BlockInterface {
return &GetHTTP{}
}
// Setup is called once before running the block. We build up the channels and specify what kind of block this is.
func (b *GetHTTP) Setup() {
b.Kind = "GetHTTP"
b.in = b.InRoute("in")
b.inrule = b.InRoute("rule")
b.queryrule = b.QueryRoute("rule")
b.quit = b.Quit()
b.out = b.Broadcast()
}
// Run is the block's main loop. Here we listen on the different channels we set up.
func (b *GetHTTP) Run() {
client := &http.Client{}
var tree *jee.TokenTree
var path string
var err error
for {
select {
case ruleI := <-b.inrule:
// set a parameter of the block
path, err = util.ParseString(ruleI, "Path")
if err != nil {
b.Error(err)
continue
}
token, err := jee.Lexer(path)
if err != nil {
b.Error(err)
continue
}
tree, err = jee.Parser(token)
if err != nil {
b.Error(err)
continue
}
case <-b.quit:
// quit the block
return
case msg := <-b.in:
// deal with inbound data
if tree == nil {
continue
}
urlInterface, err := jee.Eval(tree, msg)
if err != nil {
b.Error(err)
continue
}
urlString, ok := urlInterface.(string)
if !ok {
b.Error(errors.New("couldn't assert url to a string"))
continue
}
resp, err := client.Get(urlString)
if err != nil {
b.Error(err)
continue
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
b.Error(err)
continue
}
var outMsg interface{}
// try treating the body as json first...
err = json.Unmarshal(body, &outMsg)
// if the json parsing fails, store data unparsed as "data"
if err != nil {
outMsg = map[string]interface{}{
"data": string(body),
}
}
b.out <- outMsg
case respChan := <-b.queryrule:
// deal with a query request
respChan <- map[string]interface{}{
"Path": path,
}
}
}
}