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detect byte serving support via Content-Length [#11]

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Brandon Liu
2021-04-29 10:59:21 +08:00
parent 1252b2496c
commit 62d56f5acc
1 changed files with 15 additions and 17 deletions
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32
js/index.mjs
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@@ -37,25 +37,23 @@ const bytesToMap = dataview => {
export class PMTiles {
constructor(url, options = {}) {
this.url = url
this.root = fetch(this.url,{method:'HEAD',headers:{Range:'bytes=0-511999'}}).then(resp => {
// for servers like Azure, GH Pages which return 200 instead of 206
if (resp.status == 206 || (resp.status == 200 && options.allow_200)) {
console.log("Check succeeded: server supports byte ranges")
return fetch(this.url,{headers:{Range:'bytes=0-511999'}}).then(resp => {
return resp.arrayBuffer()
}).then(buf => {
const header = parseHeader(new DataView(buf,0,10))
var dec = new TextDecoder("utf-8")
return {
metadata: JSON.parse(dec.decode(new DataView(buf,10,header.json_size))),
dir:bytesToMap(new DataView(buf,10+header.json_size,17*header.root_entries))
}
})
} else {
console.log("Check failed: if you know this server supports byte serving, pass allow_200: true")
throw new Error("Invalid response: " + resp.status)
const controller = new AbortController()
const signal = controller.signal
this.root = fetch(this.url,{signal:signal, headers:{Range:'bytes=0-511999'}}).then(resp => {
if (resp.headers.get('Content-Length') != 512000) {
console.error("Content-Length mismatch indicates byte serving not supported; aborting.")
controller.abort()
}
return resp.arrayBuffer()
}).then(buf => {
const header = parseHeader(new DataView(buf,0,10))
var dec = new TextDecoder("utf-8")
return {
metadata: JSON.parse(dec.decode(new DataView(buf,10,header.json_size))),
dir:bytesToMap(new DataView(buf,10+header.json_size,17*header.root_entries))
}
})
this.step = 0
this.leaves = new Map()
this.outstanding_requests = new Map()