I have gone through various REST API documentation. However, I don't have a clear understanding of it. Can someone help me to understand it in layman's terms? How is it different from API being stateful? Why today all the APIs we develop are restful APIs?
Term stateless/stateful is a common term and has the same meaning for Rest API as for anything else.
Stateless means that when you make a call to some entity the response (output) will always depend on your input only. I.e. for any number of calls with the same input you will ALWAYS get the same response. Example: a request of "what is 2 + 2 equals to?" will always get you an answer 4 no matter how many times you ask and regardless if there were other queries in-between your query requests.
Stateful means that the output will depend on your input and some internal state. Example: "Please add 2 to current number that you hold. what is the new number?" (Assuming that the internal state (the current number) is 0). after the first query you will get the answer 2 but after the same query for the second time you will get answer 4 and so forth.
Each request from client to server must contain all of the information necessary to understand the request, and cannot take advantage of any stored context on the server. -- Fielding, 2000
Note that this is a constraint on semantics: all of the information that you need to understand the meaning of the request is in the request itself.
Counter example: the LIST command in FTP, where a null argument for pathname "implies the user's current working or default directory" is not stateless -- current working directory is data of session state that the server needs to remember from previous requests.
I'm developing for a web app that needs to retrieve the last 10 videos of a user(channel).
First approach
Was to use the search endpoint with param 'forMine' ordering by date, but then I figured that maybe that param could retrieve videos uploaded by the user in a diferent channel or whatever...
First result with channel ID and date - 1st Aproach
Second approach
Was to use the search endpoint with param 'channelId' ordering by date, but then I realized that descriptions were incomplete and most importantly there were some videos missing comparing with first aproach, even if the missing videos belonged to same channel (as showed in pics links)
First resutl with channel ID and date - 2nd Aproach
So, then I googled to find some solution and found other way.
Third approach
Was to use the playlistItem endpoint as I found in Google, and seemed ok (I supposed) because it returned same videos that first aproach and consumed less quota but this method left me with doubts as I didn't knew if the videos would be the latest or maybe they would be sorted by position in the playlist and couldn't be trusted to be the most recent
That said, what would be the correct way to get the N most recent videos from a channel, please?
Regardless of the quota consumption (the less quota the better, of course, but an accurate result is essential)
I'm so confussed with the API response...
Thank you so much!
-- EDITED: NEW APPROACH AND FURTHER INVESTIGATIONS --
Fourth approach
Was to use activities endpoint as was stated by #stvar in his answer. I found that this way, as on second approach, there were some videos missing comparing with first and third approaches, and it was required to retrieve everything without 'maxResults' param because there were activities not related to video upload, making mandatory to perform pagination and a self filtering by type 'upload' after retrieving response in order to get N videos (or be confident in getting N videos uploaded in first 50 retrieved items)
Self Investigations
Further investigations and tests bringed me response to the issue of 'missing videos' of some approaches.
The status of that missing videos were 'unlisted', so they were videos uploaded to the channel, property of the channel, uploaded by user of the channel... but not retrieved by some methods that seemed to retrieve only 'public' videos not 'unlisted' (hidden) nor 'private'.
NOTE: I did my test with Google API PHP Client Library, this behaviour seems not to be on 'Try this API' as it returns only 'public' items, so be careful on trust in 'Try this API' results as it seems to use some hidden filters or something...
Also I tested the channel upload playlist to verify that the order can not be changed and has a LIFO sorting
CONCLUSIONS
At this point, my self conclusion is that there is not a proper way to solve this but quite ways to do it in depend of requisites of status and amount of free quota
Search endpoint seems to work all right, if you have a good amount of unused quota (100 each call) that is the direct way and easiest one as you can sort it and filtering as needed by a bunch of params, taking care to use 'forMine' param if you need every uploaded video or 'channelId' if you need only 'listed' and 'public' ones.
PlaylistItems endpoint is a proper way if you are in a quota crisis (1 each call) as the result is sorted by recent date, taking care to do pagination and post filtering if only 'public' videos are needed till retrieve the desired amount of video ids, otherwhise you can go all the way easy.
Note that the date used to order is the upload date not the post date
(thanks to #stvar for bringing this to the attention)
Activity endpoint, also for quota crisis (1 each call), while it could be more accurate than the others if you only want public videos (it is ordered by recent 'first publish date' so not accurate 100% neither ), is for me the one that gives more work, as it retrieves activities other than 'video upload', so you can not skip pagination and post filtering to retrieve the desired amount of video ids, besides that way you only have access, as said before, to public videos (which is fine if that meets your needs).
Anyway, if you need more than 50 ids, you need to make pagination whatever the aproach you use.
Hope this help someone else and thanks so much to contributors
PS: People in charge of the YouTube API, perhaps a filter by state among some others would be interesting, Thanks!!!
You may employ the Activities.list API endpoint, queried with:
mine=true,
part=snippet,contentDetails,
fields=items(snippet(type),contentDetails(upload)), and
maxResults=50.
For to obtain your desired N uploads, you have to implement pagination. That is that you have to successively call the endpoint until you reach N result set items that have snippet.type equal with upload.
Note that you may well use channelId=CHANNEL_ID instead of mine=true, if you're interested about the most recent uploads of a channel identified by its ID CHANNEL_ID rather than your own channel.
According to the docs, you'll get from this endpoint a result set made of Activities resource items that will contain the following info:
contentDetails.upload (object)
The upload object contains information about the uploaded video. This property is only present if the snippet.type is upload.
contentDetails.upload.videoId (string)
The ID that YouTube uses to uniquely identify the uploaded video.
The official docs state that each call to Activities.list endpoint has a quota cost of one unit.
Futhermore, upon obtaining a set of video IDs, you may invoke the Videos.list endpoint with a properly assigned id parameter, for to obtain from the endpoint all the details you need for each and every video of your interest.
Note that if you have a set of video IDs of cardinality K, since the parameter id of Videos.list endpoint can be specified as a comma-separated list of video IDs, then you may reduce the number of calls to Videos.list endpoint from K to floor(K / 50) + (K % 50 ? 1 : 0) by appropriately using the feature of id just mentioned.
According to the official docs, each call to Videos.list endpoint has also a quota cost of one unit.
Clarifications upon OP's request:
Question no. 1: The Activities.list endpoint produces only the activities specified by the Activities resource. The type property enumerates them all:
snippet.type (string)
The type of activity that the resource describes.
Valid values for this property are: channelItem, comment (not currently returned), favorite, like, playlistItem, promotedItem, recommendation, social, subscription, upload, bulletin (deprecated).
Indeed your remark is correct. For example, when getting the most recent 10 uploads, is possible that you'll have to scan a number of pages P of result sets, with P >= 2, until you reached collecting the desired 10 upload items. (Actual tests have confirmed me this to be factual.)
Question no. 2: The Activities.list endpoint produces items that are sorted by publishedAt; just replace the above fields with:
fields=items(snippet(type,publishedAt),contentDetails(upload))
and see that for yourself.
I could make here the following argument justifying the necessity that the items resulted upon the invocation of Activities.list endpoint be ordered chronologically by publishedAt (the newest first). One may note that, indeed, the official docs quoted above do not specify explicitly that ordering condition I just mentioned; but bare with me for a while:
My argument is of a pragmatic kind: if the result set of Activities.list is not ordered as mentioned, then this endpoint becomes useless. This is so, since, in this case, for one to obtain the most recent upload activity would have to fetch locally all the upload activities, for to then scan that result set for the most recent one. Being compelled to fetch all upload activities only for to obtain the newest one is pragmatically a nonsense. Therefore, by way of contradiction, the result set has to be ordered chronologically by publishedAt with the newest being the first.
Question no. 3: Indeed Search.list is not precise -- it has a fuzzy behavior. I can confirm this based on my own experience; but, unfortunately, I cannot point you to official docs (from Google or YouTube) that acknowledge and explain this behavior. As unfortunate as it is, for its users Search.list is completely opaque.
On the other hand, Activities.list is precise -- it has to be like that; if it wouldn't be precise, then that's a serious bug in the implementation (in my educated opinion).
I am experimenting with the google custom search API (free version) for performing image search. I would like to commence with the paid version. However, I have some difficulties in understanding the pricing and some documented query parameters in the API calls at https://developers.google.com/custom-search/json-api/v1/using_rest#api-specific_query_parameters
1) In the free version, we have 100 queries/day. If I understood well, 1 query means a single API call. This call can return a maximum of 10 (since the parameter 'num' takes a maximum value of 10) results only. Is this both for free and paid versions? Or is it possible to retrieve more results per API request in the paid version? Precisely, can 'num' take values greater than 10?
2) The parameter 'start' is documented as index of the first result to return. In the free version, I cannot get more than 100 results for a specific query (parameter 'q'). To summarize precisely, I can get 10 results/API call, each call with parameter 'start' taking the values 1, 11,... 91 and same value for 'q'. The API call returns an error for any value of 'start' greater than 91. Is n't the free version supposed to allow 100 API calls? Or perhaps, this restriction is placed to avoid being able to retrieve more than 100 results per search term 'q'?
3) In the paid version, are API calls which return non-200 responses billed for as well?
4) In the paid version, how many API calls can be made for a specific search term 'q'?
5) Do you think there are particular restrictions with respect to the number of results that apply specific to image search only?
Thanks in advance for your help.
The results are paginated. The search results show 10 per page. If you want more you need to set the start page to 11 & get 10 more. It is an exact imitation of what would happen in Google UI search. If you have trouble understanding goto Google search and observe the results. It should match almost. parameter n must be the number of results per page.
In the free version you have 100 free/day. Anything else will 0.5 cents per request. You cannot make more 10k calls per day. So free is not actually free.
In the "paid" version you can buy in bulk. AFAIK there is no daily limit. You can "buy" let us say 11000 requests for 55$ (11000*0.5) and use it all up in one day. But the paid version will be ended soon :( . Please check this blog for info https://customsearch.googleblog.com/
I'm trying to use Google Places API for a business locator app, but am having trouble creating an exhaustive database of business.
1.The API call only returns 20 results back.
2.The "type" restriction (e.g. type=restaurant) does not pick up all businesses by type in a given zip. I could use "keyword" but not all restaurants have restaurant in their name, and not all spas have "spa" in their name.
3. Each call produces the same set of results from day to day, and with only 20 returns per call, how am I to get a more exhaustive database of businesses?
I can try to get around the above three constraints by looping through a very well degraded search of businesses: say by zip code, some list of keywords, category type. But I still won't get close to picking up the 50 million or so businesses in google places.
In fact, even when I make a call for restaurants and bars in my own neighborhood, I don't pick up popular places down the block from me.
How is the API usable for an app that locates places then?
Any suggestions on how to create a more exhaustive search?
Thanks,
Nad
I'm not able to answer your question regarding Google Places API.
But for your requirements ('business locator app', 'I don't pick up popular places down the block from me') I suggest you try Yelp Search API:
Yelp's API program enables you to access trusted Yelp information in real time, such as business listing info, overall business ratings and review counts, deals and recent review excerpts.
Yelp is a popular review website with a capable API and you may test the quality of database and the devoted user base they have at Yelp homepage.
Note:
They keep some data for themselves and do not return everything in response.
The (free) dev account has a limit of 100 calls per 24 hours.
I know I'm late but maybe it helps someone these days.
By default, each Nearby Search or Text Search returns up to 20
establishment results per query; however, each search can return as
many as 60 results, split across three pages.
You need to use the field nextPageToken that you will receive on the first search to get the next page.
https://developers.google.com/places/web-service/search
An issue in stack overflow says:
There is no way to get more than 60 results in Places API. Some people
tried to file a feature request in Google issue tracker, but Google
rejected it with the following comment Unfortunately Places API is not
in a position to return more than 60 results. Besides technical
reasons (latency, among others) returning more than 60 results would
make the API be more like a database or general-purpose search engine.
We'd rather improve search quality so that users don't need to go so
far down a long list of results.
google places api more than 60 results
I faced the same difficulties that you did and decided to use the Yelp API instead. It is free, very complete and returns up to 1000 results. You should however check the terms of service before doing anything. It does not provide the website of the business (only the Yelp website link).
https://www.yelp.com/developers/documentation/v3/business_search
Other options I investigated at that time:
Foursquare ventures. (It was very expensive, and only returned up to around 100 results)
Here places API
Factual Places (I don't think this one is an API)
Sygic Travel API (Specific for touristical spots)
Planet.osm (OpenStreetMap)
I am making an app using twitter API that needs to use the twitter REST API to find the followers of a user frequently . But twitter has a restriction of 350 API requests in an hour . My App in its current state is sure to exceed that. Please tell me what kind of caching strategy should I employ to reduce the number of API calls I make and thereby improve speed of my app and the follow twitter policies without any problem.
Abstract your access to Twitter API and do something along these lines.
If last call to Twitter at least 12 seconds ago
Make new call to Twitter and store returned info
Set Timestamp
else
Return last stored data
endif
This means that only one part of your program needs to know about the restriction and all other parts can treat the data as having come fresh from Twitter.
In the light of your comment, the above pseudo-code becomes
If last call to Twitter at least 12 seconds ago
Make new call to Twitter and save follower list in DB
Set Timestamp
endif
Return follower list from DB
I would be inclined to have this sort of structure in one table, at least at first.
twitter_id
.
.
whatever else you want to store about the person
.
.
followers VARCHAR space-separated list of follower IDs
Obviously, this would be a simplistic approach, but on the basis of 'the simplest thing that works' it would be fine.