I'm trying to find a way to write json data to a file in a Google Cloud Storage bucket, inside of a promise.
What I'm finding is that if I try and .push() the values to an array one by one and then return that, it only gives me the first 3 results from the array (whereas console.log will return everything).
And if I try and write something within the local scope, it only returns the last value from the array (and overwrites all the previous values rather than appending them).
So essentially my question is: is there any way to write a promise or similar that will wait for all the looped through values to be gathered up, and once that's done return those values to a function that will then upload it all to GCS?
Or is there a way in which I can write these values to the .json file in GCS asynchronously, at the same time as the data is being scraped?
const urls = [/* 20+ URLs go here... */];
let promises = [];
// Build array of Promises
urls.map(function(url) {
promises.push(axios.get(url));
});
// Map through the array of promises and get the response results
axios.all(promises).then((results) => {
results.map((res) => {
try {
// Scrape the data
const $ = new JSDOM(res.data);
const data = {};
data.title = ($.window.document.querySelector('head > title') !== null ? $.window.document.querySelector('head > title').text : '');
data.description = ($.window.document.querySelector("meta[name='description']") !== null ? $.window.document.querySelector('meta[name="description"]').content : '');
data.robots = ($.window.document.querySelector("meta[name='robots']") !== null ? $.window.document.querySelector("meta[name='robots']").content : '');
const value = JSON.stringify(data) + '\n';
// Tried array.push(value) here but doesn't return all the values?
// Any way to return all the values and then bulk upload them to GCS outside of this code block?
const file = storage.bucket(bucketName).file(filename);
file.save(value, function(err) {
if (!err) {
// file written
}
})
} catch(e) {
console.log(e);
}
})
})
Sorry for the poor explanation, essentially I can't push all the values to an array and then upload that, and if I try to upload the values one by one I only get the last value in the looped through array.
Note: I'm not trying to save the data to a .json file locally with fs.writeFile() and then upload to GCS but send the JSON data directly to GCS without the step in between.
if i correctly understood what do you need it should work
axios.all(promises).then((results) => {
const uploads = results.map((res) => {
try {
// Scrape the data
const $ = new JSDOM(res.data);
const data = {};
data.title = ($.window.document.querySelector('head > title') !== null ? $.window.document.querySelector('head > title').text : '');
data.description = ($.window.document.querySelector("meta[name='description']") !== null ? $.window.document.querySelector('meta[name="description"]').content : '');
data.robots = ($.window.document.querySelector("meta[name='robots']") !== null ? $.window.document.querySelector("meta[name='robots']").content : '');
const value = JSON.stringify(data) + '\n';
return new Promise((resolve, reject) => {
const file = storage.bucket(bucketName).file(filename);
file.save(value, function(err) {
if (!err) {
resolve()
}
reject()
})
});
} catch(e) {
console.log(e);
}
})
return Promise.all(uploads);
})
Related
I am trying to fetch JSON data from the WordPress Developer Reference site. I need to search a keyword without knowing if it's a function, class, hook, or method, which is part of the url I need to fetch. So I'm using Promise.all to cycle through all possible urls. It works if the response.status <= 299, throwing the error immediately, and if the response is ok, then it continues to .then. Fine, but occasionally it will return an ok status if the JSON exists and only returns an empty array. So I need to check if the JSON data is an empty array, which I can't seem to do in the first part. I can only check in the second part as far as I know. And if it throws the error it doesn't continue trying the other urls. Any suggestions?
var keyword = 'AtomParser';
const refs = ['function', 'hook', 'class', 'method'];
// Store the promises
let promises = [];
// Cycle through each type until we find one we're looking for
for (let t = 0; t < refs.length; t++) {
const url =
'https://developer.wordpress.org/wp-json/wp/v2/wp-parser-' +
refs[t] +
'?search=' +
keyword;
// console.log(url);
promises.push(fetch(url));
}
Promise.all(promises)
.then(function(response) {
console.log(response[0]);
// Get the status
console.log('Status code: ' + response[0].status);
if (response[0].status <= 299) {
// The API call was successful!
return response[0].json();
} else {
throw new Error('Broken link status code: ' + response[0].status);
}
})
.then(function(data) {
// This is the HTML from our response as a text string
console.log(data);
// Make sure we have data
if (data.length == 0) {
throw new Error('Empty Array');
}
// ref
const reference = data[0];
// Only continue if not null or empty
if (reference !== null && reference !== undefined && data.length > 0) {
// Success
// Return what I want from the reference
}
})
.catch(function handleError(error) {
console.log('Error' + error);
});
Is there some way to get the JSON data in the first part so I can check if it's in an array while I'm checking the response status?
I would recommend encapsulating the success / failure logic for individual requests, then you can determine all the resolved and rejected responses based on the result of that encapsulation.
For example
const checkKeyword = async (ref, keyword) => {
const params = new URLSearchParams({ search: keyword });
const res = await fetch(
`https://developer.wordpress.org/wp-json/wp/v2/wp-parser-${encodeURIComponent(
ref
)}?${params}`
);
if (!res.ok) {
throw new Error(`${res.status}: ${await res.text()}`);
}
const data = await res.json();
if (data.length === 0) {
throw new Error(`Empty results for '${ref}'`);
}
return { ref, data };
};
Now you can use something like Promise.any() or Promise.allSettled() to find the first successful request or all successful requests, respectively
const keyword = "AtomParser";
const refs = ["function", "hook", "class", "method"];
const promises = refs.map((ref) => checkKeyword(ref, keyword));
// First success
Promise.any(promises)
.then(({ ref, data }) => {
console.log(ref, data);
})
.catch(console.error);
// All successes
Promise.allSettled(promises)
.then((responses) =>
responses.reduce(
(arr, { status, value }) =>
status === "fulfilled" ? [...arr, value] : arr,
[]
)
)
.then((results) => {
// results has all the successful responses
});
For whatever reason I couldn't get Phil's answer to work, so I ended up doing the following which works fine for me. (This is for a discord bot in case you're wondering what the other stuff is all about).
var keyword = 'AtomParser';
const refs = ['function', 'hook', 'class', 'method'];
// Store the successful result or error
let final: any[] = [];
let finalError = '';
// Cycle through each type until we find one we're looking for
for (let t = 0; t < refs.length; t++) {
const url =
'https://developer.wordpress.org/wp-json/wp/v2/wp-parser-' +
refs[t] +
'?search=' +
keyword;
console.log(url);
// Try to fetch it
await fetch(url)
.then(function (response) {
console.log(response);
// Get the status
console.log('Status code: ' + response.status);
if (response.status > 299) {
finalError = '`' + refs[t] + '` does not exist.';
throw new Error(finalError);
} else {
// The API call was successful!
return response.json();
}
})
.then(function (data) {
// This is the HTML from our response as a text string
console.log(data);
// Make sure we have data
if (data.length == 0) {
finalError = "Sorry, I couldn't find `" + keyword + '`';
throw new Error(finalError);
}
// Only continue if not null or empty
if (data[0] !== null && data[0] !== undefined && data.length > 0) {
for (let d = 0; d < data.length; d++) {
// Add it to the final array
final.push(data[d]);
}
}
})
.catch(function handleError(error) {
console.log(error);
});
}
if (final.length > 0) {
for (let f = 0; f < final.length; f++) {
// ref
const reference = final[f];
// Get the link
const link = reference.link;
// Get the title
var title = reference.title.rendered;
title = excerpt.replace('>', '>');
// Get the excerpt
var excerpt = reference.excerpt.rendered;
excerpt = excerpt.replace('<p>', '');
excerpt = excerpt.replace('</p>', '');
excerpt = excerpt.replace('<b>', '**');
excerpt = excerpt.replace('</b>', '**');
console.log(excerpt);
message.reply(
new discord.Embed({
title: `${title}`,
url: link,
description: `${excerpt}\n\n`,
footer: {
text: `WordPress Developer Code Reference\nhttps://developer.wordpress.org/`,
},
})
);
}
} else if (finalError != '') {
message.reply(finalError);
} else {
message.reply('Something went wrong...');
}
wp module
#Phil's answer puts you on the right track but I want to expand on some of his ideas. Use of URLSearchParamas is great but you can improve by using the high-level URL API and forego encodeURIComponent and constructing search params manually. Notice I'm putting this code in its own wp module so I can separate concerns more easily. We don't want all of this code leaking into your main program.
// wp.js
import { fetch } from "whatwg-fetch" // or your chosen implementation
const baseURL = "https://developer.wordpress.org"
async function search1(path, query) {
const u = new URL(path, baseURL)
u.searchParams.set("search", query)
const result = await fetch(u)
if (!result.ok) throw Error(`Search failed (${result.status}): ${u}`)
return result.json()
}
search1 searches one path, but we can write search to search all the necessary paths. I don't think there's any reason to get fancy with each path here, so just write them out -
// wp.js (continued)
function search(query) {
const endpoints = [
"/wp-json/wp/v2/wp-parser-function",
"/wp-json/wp/v2/wp-parser-hook",
"/wp-json/wp/v2/wp-parser-class",
"/wp-json/wp/v2/wp-parser-method"
]
return Promise
.all(endpoints.map(e => search1(e, query)))
.then(results => results.flat())
}
export { search }
main module
Notice we only exported search as search1 is internal to the wp module. Let's see how we can use it in our main module now -
// main.js
import { search } from "./wp.js"
for (const result of await search("database"))
if(result.guid.rendered)
console.log(`${result.title.rendered}\n${result.guid.rendered}\n`)
In this example, we first search for "database" -
wp_should_replace_insecure_home_url()
https://developer.wordpress.org/reference/functions/wp_should_replace_insecure_home_url/
wp_delete_signup_on_user_delete()
https://developer.wordpress.org/reference/functions/wp_delete_signup_on_user_delete/
get_post_datetime()
https://developer.wordpress.org/reference/functions/get_post_datetime/
wp_ajax_health_check_get_sizes()
https://developer.wordpress.org/reference/functions/wp_ajax_health_check_get_sizes/
wp_should_replace_insecure_home_url
https://developer.wordpress.org/reference/hooks/wp_should_replace_insecure_home_url/
comments_pre_query
https://developer.wordpress.org/reference/hooks/comments_pre_query/
users_pre_query
https://developer.wordpress.org/reference/hooks/users_pre_query/
WP_Object_Cache
http://developer.wordpress.org/reference/classes/wp_object_cache/
wpdb
http://developer.wordpress.org/reference/classes/wpdb/
WP_REST_Menu_Items_Controller::prepare_item_for_database()
https://developer.wordpress.org/reference/classes/wp_rest_menu_items_controller/prepare_item_for_database/
WP_REST_Global_Styles_Controller::prepare_item_for_database()
https://developer.wordpress.org/reference/classes/wp_rest_global_styles_controller/prepare_item_for_database/
WP_REST_Menus_Controller::prepare_item_for_database()
https://developer.wordpress.org/reference/classes/wp_rest_menus_controller/prepare_item_for_database/
WP_REST_Templates_Controller::prepare_item_for_database()
https://developer.wordpress.org/reference/classes/wp_rest_templates_controller/prepare_item_for_database/
WP_REST_Application_Passwords_Controller::prepare_item_for_database()
https://developer.wordpress.org/reference/classes/wp_rest_application_passwords_controller/prepare_item_for_database/
wpdb::db_server_info()
https://developer.wordpress.org/reference/classes/wpdb/db_server_info/
WP_REST_Attachments_Controller::insert_attachment()
https://developer.wordpress.org/reference/classes/wp_rest_attachments_controller/insert_attachment/
WP_Debug_Data::get_database_size()
https://developer.wordpress.org/reference/classes/wp_debug_data/get_database_size/
WP_REST_Meta_Fields::update_multi_meta_value()
https://developer.wordpress.org/method/wp_rest_meta_fields/update_multi_meta_value/
another search example
Now let's search for "image" -
for (const result of await search("image"))
if(result.guid.rendered)
console.log(`${result.title.rendered}\n${result.guid.rendered}\n`)
get_adjacent_image_link()
https://developer.wordpress.org/reference/functions/get_adjacent_image_link/
get_next_image_link()
https://developer.wordpress.org/reference/functions/get_next_image_link/
get_previous_image_link()
https://developer.wordpress.org/reference/functions/get_previous_image_link/
wp_robots_max_image_preview_large()
https://developer.wordpress.org/reference/functions/wp_robots_max_image_preview_large/
wp_getimagesize()
https://developer.wordpress.org/reference/functions/wp_getimagesize/
is_gd_image()
https://developer.wordpress.org/reference/functions/is_gd_image/
wp_show_heic_upload_error()
https://developer.wordpress.org/reference/functions/wp_show_heic_upload_error/
wp_image_src_get_dimensions()
https://developer.wordpress.org/reference/functions/wp_image_src_get_dimensions/
wp_image_file_matches_image_meta()
https://developer.wordpress.org/reference/functions/wp_image_file_matches_image_meta/
_wp_check_existing_file_names()
https://developer.wordpress.org/reference/functions/_wp_check_existing_file_names/
edit_custom_thumbnail_sizes
https://developer.wordpress.org/reference/hooks/edit_custom_thumbnail_sizes/
get_header_image_tag_attributes
https://developer.wordpress.org/reference/hooks/get_header_image_tag_attributes/
image_editor_output_format
https://developer.wordpress.org/reference/hooks/image_editor_output_format/
wp_image_src_get_dimensions
https://developer.wordpress.org/reference/hooks/wp_image_src_get_dimensions/
wp_get_attachment_image
https://developer.wordpress.org/reference/hooks/wp_get_attachment_image/
image_sideload_extensions
https://developer.wordpress.org/reference/hooks/image_sideload_extensions/
wp_edited_image_metadata
https://developer.wordpress.org/reference/hooks/wp_edited_image_metadata/
wp_img_tag_add_loading_attr
https://developer.wordpress.org/reference/hooks/wp_img_tag_add_loading_attr/
wp_image_file_matches_image_meta
https://developer.wordpress.org/reference/hooks/wp_image_file_matches_image_meta/
get_custom_logo_image_attributes
https://developer.wordpress.org/reference/hooks/get_custom_logo_image_attributes/
Custom_Image_Header
http://developer.wordpress.org/reference/classes/custom_image_header/
WP_Image_Editor_Imagick
http://developer.wordpress.org/reference/classes/wp_image_editor_imagick/
WP_Embed
http://developer.wordpress.org/reference/classes/wp_embed/
WP_Image_Editor
http://developer.wordpress.org/reference/classes/wp_image_editor/
WP_Customize_Background_Image_Setting
http://developer.wordpress.org/reference/classes/wp_customize_background_image_setting/
WP_Customize_Header_Image_Setting
http://developer.wordpress.org/reference/classes/wp_customize_header_image_setting/
WP_Image_Editor_GD
http://developer.wordpress.org/reference/classes/wp_image_editor_gd/
WP_Customize_Header_Image_Control
http://developer.wordpress.org/reference/classes/wp_customize_header_image_control/
WP_REST_Server::add_image_to_index()
https://developer.wordpress.org/reference/classes/wp_rest_server/add_image_to_index/
WP_REST_URL_Details_Controller::get_image()
https://developer.wordpress.org/reference/classes/wp_rest_url_details_controller/get_image/
WP_Image_Editor::get_default_quality()
https://developer.wordpress.org/reference/classes/wp_image_editor/get_default_quality/
WP_Theme_JSON::get_blocks_metadata()
https://developer.wordpress.org/reference/classes/wp_theme_json/get_blocks_metadata/
WP_Image_Editor_Imagick::pdf_load_source()
https://developer.wordpress.org/reference/classes/wp_image_editor_imagick/pdf_load_source/
WP_Image_Editor_Imagick::write_image()
https://developer.wordpress.org/reference/classes/wp_image_editor_imagick/write_image/
WP_Image_Editor_Imagick::maybe_exif_rotate()
https://developer.wordpress.org/reference/classes/wp_image_editor_imagick/maybe_exif_rotate/
WP_Image_Editor_Imagick::make_subsize()
https://developer.wordpress.org/reference/classes/wp_image_editor_imagick/make_subsize/
WP_Image_Editor_GD::make_subsize()
https://developer.wordpress.org/reference/classes/wp_image_editor_gd/make_subsize/
empty search result
Searching for "zzz" will yield no results -
for (const result of await search("zzz"))
if(result.guid.rendered)
console.log(`${result.title.rendered}\n${result.guid.rendered}\n`)
<empty result>
Problem Statement:
Our aim is to allocate values in the array ytQueryAppJs, which are returned from a time consuming function httpsYtGetFunc().
The values in ytQueryAppJs needs to be used many times in further part of the code, hence it needs to be done 'filled', before the code proceeds further.
There are many other arrays like ytQueryAppJs, namely one of them is ytCoverAppJs, that needs to be allocated the value, the same way as ytQueryAppJs.
The values in ytCoverAppJs further require the use of values from ytQueryAppJs. So a solution with clean code would be highly appreciated.
(I am an absolute beginner. I have never used async, await or promises and I'm unaware of the correct way to use it. Please guide.)
Flow (to focus on):
The user submits a queryValue in index.html.
An array ytQueryAppJs is logged in console, based on the query.
Expected Log in Console (similar to):
Current Log in Console:
Flow (originally required by the project):
User submits query in index.html.
The values of arrays, ytQueryAppJs, ytCoverAppJs, ytCoverUniqueAppJs, ytLiveAppJs, ytLiveUniqueAppJs gets logged in the console, based on the query.
Code to focus on, from 'app.js':
// https://stackoverflow.com/a/14930567/14597561
function compareAndRemove(removeFromThis, compareToThis) {
return (removeFromThis = removeFromThis.filter(val => !compareToThis.includes(val)));
}
// Declaring variables for the function 'httpsYtGetFunc'
let apiKey = "";
let urlOfYtGetFunc = "";
let resultOfYtGetFunc = "";
let extractedResultOfYtGetFunc = [];
// This function GETs data, parses it, pushes required values in an array.
async function httpsYtGetFunc(queryOfYtGetFunc) {
apiKey = "AI...MI"
urlOfYtGetFunc = "https://www.googleapis.com/youtube/v3/search?key=" + apiKey + "&part=snippet&q=" + queryOfYtGetFunc + "&maxResults=4&order=relevance&type=video";
let promise = new Promise((resolve, reject) => {
// GETting data and storing it in chunks.
https.get(urlOfYtGetFunc, (response) => {
const chunks = []
response.on('data', (d) => {
chunks.push(d)
})
// Parsing the chunks
response.on('end', () => {
resultOfYtGetFunc = JSON.parse((Buffer.concat(chunks).toString()))
// console.log(resultOfYtGetFunc)
// Extracting useful data, and allocating it.
for (i = 0; i < (resultOfYtGetFunc.items).length; i++) {
extractedResultOfYtGetFunc[i] = resultOfYtGetFunc.items[i].id.videoId;
// console.log(extractedResultOfYtGetFunc);
}
resolve(extractedResultOfYtGetFunc);
})
})
})
let result = await promise;
return result;
}
app.post("/", function(req, res) {
// Accessing the queryValue, user submitted in index.html. We're using body-parser package here.
query = req.body.queryValue;
// Fetching top results related to user's query and putting them in the array.
ytQueryAppJs = httpsYtGetFunc(query);
console.log("ytQueryAppJs:");
console.log(ytQueryAppJs);
});
Complete app.post method from app.js:
(For better understanding of the problem.)
app.post("/", function(req, res) {
// Accessing the queryValue user submitted in index.html.
query = req.body.queryValue;
// Fetcing top results related to user's query and putting them in the array.
ytQueryAppJs = httpsYtGetFunc(query);
console.log("ytQueryAppJs:");
console.log(ytQueryAppJs);
// Fetching 'cover' songs related to user's query and putting them in the array.
if (query.includes("cover") == true) {
ytCoverAppJs = httpsYtGetFunc(query);
console.log("ytCoverAppJs:");
console.log(ytCoverAppJs);
// Removing redundant values.
ytCoverUniqueAppJs = compareAndRemove(ytCoverAppJs, ytQueryAppJs);
console.log("ytCoverUniqueAppJs:");
console.log(ytCoverUniqueAppJs);
} else {
ytCoverAppJs = httpsYtGetFunc(query + " cover");
console.log("ytCoverAppJs:");
console.log(ytCoverAppJs);
// Removing redundant values.
ytCoverUniqueAppJs = compareAndRemove(ytCoverAppJs, ytQueryAppJs);
console.log("ytCoverUniqueAppJs:");
console.log(ytCoverUniqueAppJs);
}
// Fetching 'live performances' related to user's query and putting them in the array.
if (query.includes("live") == true) {
ytLiveAppJs = httpsYtGetFunc(query);
console.log("ytLiveAppJs:");
console.log(ytLiveAppJs);
// Removing redundant values.
ytLiveUniqueAppJs = compareAndRemove(ytLiveAppJs, ytQueryAppJs.concat(ytCoverUniqueAppJs));
console.log("ytLiveUniqueAppJs:");
console.log(ytLiveUniqueAppJs);
} else {
ytLiveAppJs = httpsYtGetFunc(query + " live");
console.log("ytLiveAppJs:");
console.log(ytLiveAppJs);
// Removing redundant values.
ytLiveUniqueAppJs = compareAndRemove(ytLiveAppJs, ytQueryAppJs.concat(ytCoverUniqueAppJs));
console.log("ytLiveUniqueAppJs:");
console.log(ytLiveUniqueAppJs);
}
// Emptying all the arrays.
ytQueryAppJs.length = 0;
ytCoverAppJs.length = 0;
ytCoverUniqueAppJs.length = 0;
ytLiveAppJs.length = 0;
ytLiveUniqueAppJs.length = 0;
});
Unfortunately you can use the async/await on http module when making requests. You can install and use axios module . In your case it will be something like this
const axios = require('axios');
// Declaring variables for the function 'httpsYtGetFunc'
let apiKey = "";
let urlOfYtGetFunc = "";
let resultOfYtGetFunc = "";
let extractedResultOfYtGetFunc = [];
// This function GETs data, parses it, pushes required values in an array.
async function httpsYtGetFunc(queryOfYtGetFunc) {
apiKey = "AI...MI"
urlOfYtGetFunc = "https://www.googleapis.com/youtube/v3/search?key=" + apiKey + "&part=snippet&q=" + queryOfYtGetFunc + "&maxResults=4&order=relevance&type=video";
const promise = axios.get(urlOfYtGetFunc).then(data => {
//do your data manipulations here
})
.catch(err => {
//decide what happens on error
})
Or async await
const data = await axios.get(urlOfYtGetFunc);
//Your data variable will become what the api has returned
If you still want to catch errors on async await you can use try catch
try{
const data = await axios.get(urlOfYtGetFunc);
}catch(err){
//In case of error do something
}
I have just looked at the code I think the issue is how you are handling the async code in the request handler. You are not awaiting the result of the function call to httpsYtGetFunc in the body so when it returns before the promise is finished which is why you get the Promise {Pending}.
Another issue is that the array is not extractedResultOfYtGetFunc is not initialised and you may access indexes that don't exist. The method to add an item to the array is push.
To fix this you need to restructure your code slightly. A possible solution is something like this,
// Declaring variables for the function 'httpsYtGetFunc'
let apiKey = "";
let urlOfYtGetFunc = "";
let resultOfYtGetFunc = "";
let extractedResultOfYtGetFunc = [];
// This function GETs data, parses it, pushes required values in an array.
function httpsYtGetFunc(queryOfYtGetFunc) {
apiKey = "AI...MI";
urlOfYtGetFunc =
"https://www.googleapis.com/youtube/v3/search?key=" +
apiKey +
"&part=snippet&q=" +
queryOfYtGetFunc +
"&maxResults=4&order=relevance&type=video";
return new Promise((resolve, reject) => {
// GETting data and storing it in chunks.
https.get(urlOfYtGetFunc, (response) => {
const chunks = [];
response.on("data", (d) => {
chunks.push(d);
});
// Parsing the chunks
response.on("end", () => {
// Initialising the array
extractedResultOfYtGetFunc = []
resultOfYtGetFunc = JSON.parse(Buffer.concat(chunks).toString());
// console.log(resultOfYtGetFunc)
// Extracting useful data, and allocating it.
for (i = 0; i < resultOfYtGetFunc.items.length; i++) {
// Adding the element to the array
extractedResultOfYtGetFunc.push(resultOfYtGetFunc.items[i].id.videoId);
// console.log(extractedResultOfYtGetFunc);
}
resolve(extractedResultOfYtGetFunc);
});
});
});
}
app.post("/", async function (req, res) {
query = req.body.queryValue;
// Fetching top results related to user's query and putting them in the array.
ytQueryAppJs = await httpsYtGetFunc(query);
console.log("ytQueryAppJs:");
console.log(ytQueryAppJs);
});
Another option would be to use axios,
The code for this would just be,
app.post("/", async function (req, res) {
query = req.body.queryValue;
// Fetching top results related to user's query and putting them in the array.
try{
ytQueryAppJs = await axios.get(url); // replace with your URL
console.log("ytQueryAppJs:");
console.log(ytQueryAppJs);
} catch(e) {
console.log(e);
}
});
Using Axios would be a quicker way as you don't need to write promise wrappers around everything, which is required as the node HTTP(S) libraries don't support promises out of the box.
I'm working with mongodb stitch/realm and I'm trying to modify objects inside an array with a foreach and also pushing ids into a new array.
For each object that i'm modifying, I'm also doing a query first, after the document is found I start modifying the object and then pushing the id into another array so I can use both arrays later.
The code is something like this:
exports = function(orgLoc_id, data){
var HttpStatus = require('http-status-codes');
// Access DB
const db_name = context.values.get("database").name;
const db = context.services.get("mongodb-atlas").db(db_name);
const orgLocPickupPointCollection = db.collection("organizations.pickup_points");
const orgLocStreamsCollection = db.collection("organizations.streams");
const streamsCollection = db.collection("streams");
let stream_ids = [];
data.forEach(function(stream) {
return streamsCollection.findOne({_id: stream.stream_id}, {type: 1, sizes: 1}).then(res => { //if I comment this query it will push without any problem
if(res) {
let newId = new BSON.ObjectId();
stream._id = newId;
stream.location_id = orgLoc_id;
stream.stream_type = res.type;
stream.unit_price = res.sizes[0].unit_price_dropoff;
stream._created = new Date();
stream._modified = new Date();
stream._active = true;
stream_ids.push(newId);
}
})
})
console.log('stream ids: ' + stream_ids);
//TODO
};
But when I try to log 'stream_ids' it's empty and nothing is shown. Properties stream_type and unit_price are not assigned.
I've tried promises but I haven't had success
It's an asynchronous issue. You're populating the value of the array inside a callback. But because of the nature of the event loop, it's impossible that any of the callbacks will have been called by the time the console.log is executed.
You mentioned a solution involving promises, and that's probably the right tack. For example something like the following:
exports = function(orgLoc_id, data) {
// ...
let stream_ids = [];
const promises = data.map(function(stream) {
return streamsCollection.findOne({ _id: stream.stream_id }, { type: 1, sizes: 1 })
.then(res => { //if I comment this query it will push without any problem
if (res) {
let newId = new BSON.ObjectId();
// ...
stream_ids.push(newId);
}
})
})
Promise.all(promises).then(function() {
console.log('stream ids: ' + stream_ids);
//TODO
// any code that needs access to stream_ids should be in here...
});
};
Note the change of forEach to map...that way you're getting an array of all the Promises (I'm assuming your findOne is returning a promise because of the .then).
Then you use a Promise.all to wait for all the promises to resolve, and then you should have your array.
Side note: A more elegant solution would involve returning newId inside your .then. In that case Promise.all will actually resolve with an array of the results of all the promises, which would be the values of newId.
I'm working on my front-end, and I've arrived at a roadblock. I'm trying to fetch data from my back-end, and it is actually fetching the data. But only after everything else? I'll show you.
$(function(){
function GetURLId() {
var url = window.location.href;
var path = url.substring(url.lastIndexOf('/') + 1);
var id = path.substring(path.lastIndexOf('?id=') + 4, path.lastIndexOf("?id") + 5)
return id;
}
var url = 'https://localhost:5001/api/rental/byId/' + GetURLId();
fetch(url)
.then((resp) => resp.json())
.then(function(data) {
Object.keys(data).forEach(key => {
console.log(`${key}: ${data[key]}`);
})
});
});
So first I get which id I'm working with out of the URL. Then where the problem lays is the code under it. I'm able to fetch my data as it console.logs this:
id: 2
status: "Open"
damage: true
So the data does actually fetch from my back-end. But now, everytime I try to save the data it goes undefined. I've tried:
$(function(){
var rental = []; // Added an array
var url = 'https://localhost:5001/api/rental/byId/' + GetURLId();
fetch(url)
.then((resp) => resp.json())
.then(function(data) {
Object.keys(data).forEach(key => {
console.log(`${key}: ${data[key]}`);
rental.push(rental[key] = data[key]);
})
});
console.log(rental['id']); // Returns undefined
});
And:
var rental = []; // Added an array outside of the function
$(function(){
var url = 'https://localhost:5001/api/rental/byId/' + GetURLId();
fetch(url)
.then((resp) => resp.json())
.then(function(data) {
Object.keys(data).forEach(key => {
console.log(`${key}: ${data[key]}`);
rental.push(rental[key] = data[key]);
})
});
console.log(rental['id']); // Returns undefined
});
But! With the last one where the rental is outside of the function, I can actually call it in the console. And in the console it actually does return the value.
Inside Console:
> rental["id"]
< 2
Lastly I've tried to check the value of the key and value inside of the fetch, like this:
$(function(){
var url = 'https://localhost:5001/api/rental/byId/' + GetURLId();
fetch(url)
.then((resp) => resp.json())
.then(function(data) {
Object.keys(data).forEach(key => {
if(key == "status" && data[key] != "Reserved") {
console.log(`${key}: ${data[key]}`); // Returns damage: undefined 3 times
}
})
});
});
But this as well doesn't work. It returns damage: undefined 3 times in console.
So if anyone knows what is going on here it would be awesome!
Thanks alot in advance.
Fetch requests are asynchronous. This means that when you call fetch it might take a while to complete it, so JavaScript allows the rest of the code to continue without blocking. So logging anything to the console before your request has finished will obviously result in an empty array.
Also, Arrays are index-, not name based in JavaScript. However, because arrays are essentially objects it still works, but you should never do the following below.
var rental = [];
rental['id'] = 'foo';
console.log(rental['id']);
Instead use a plain object which is meant to be used that way.
var rental = {};
rental['id'] = 'foo';
console.log(rental['id']);
In your last example you seem to do everything just fine. Are you sure your fetched data does not have a value of undefined in its structure? It would help to see what the data looks like.
The answer: 2 errors in my code.
- First I didn't properly account for the asynchronous nature of the code.
- Second, when trying to fix it with another then block and executing my code in there. I didn't return a value in the proceeding then block, but the forEach instead.
fetch(url)
.then(resp => resp.json())
.then(data => {
var rentalStatus;
Object.keys(data).forEach(key => {
rental[key] = data[key];
if(key == "status") {
rentalStatus = data[key];
}
})
return rentalStatus;
})
.then(rentalStatus => {
console.log(rental["id"]); // This does return the id now!
if(rentalStatus == "Reserved") {
$("#assign-items").removeClass("d-none");
}
}).catch(error => {
console.log("Error:" + error);
});
I have been working to make a small app to get the images and info from the pokemon api at http://pokeapi.co/ , I am following course using promises however I can get a group (example: water type) which give me 78 objects , each one with a resource_uri which is the data which give me the information of each pokemon.
Until now I have make this and I can get all the objects, however, now how can I make in order to get for each object push in the console.log (or later use them) all the 78pokemons with the data of each.
My code until now is this>
var $ = window.jQuery
var base = 'http://pokeapi.co/api/v1/egg/'
Promise.resolve($.get(base + '2'))
.then((results) =>
.then((results) => {
var pokechara = results.pokemon
var basechara = 'http://pokeapi.co'
var promises = []
for (let chara of pokechara){
var pokech = pokechara[i]
'${something}'
var pokechurl = basechara + pokechara[0].resource_uri
promises.push(Promise.resolve($.get(pokechurl)))
}
debugger
return Promise.all(promises)
})
.then((poke) => {
console.log(poke)
})
.catch((err) => {
debugger
})
I really wanted to make something with the api of yugioh.wikia but I dont see how I can get work because the problem with the Cros-server or header. To see a preview of what I am doing you can see at http://www.kengreg.com/yugiohapp/
Thanks in advance
Actually, in the code used in your reply to Alex, the string variables you use to call the api are the only thing wrong, the 'http://' part at the start is needed. Apart from that, your code works fine.
var $ = window.jQuery;
var base = 'http://pokeapi.co/api/v1/egg/';
Promise.resolve($.get(base + '2'))
.then((results) => {
var pokechara = results.pokemon;
var basechara = 'http://pokeapi.co/';
var promises = [];
for (var i in pokechara){
var pokech = pokechara[i];
var pokechurl = basechara + pokechara[0].resource_uri;
promises.push(Promise.resolve($.get(pokechurl)));
}
debugger
return Promise.all(promises);
})
.then((poke) => {
debugger;
console.log(poke);
})
.catch((err) => { debugger })
I left the debugger so you can checkout the results of the promises. The poke variable at the end should have the objects array you wanted.